diff --git a/CHANGELOG.md b/CHANGELOG.md
index db6cb5ffb..b03e6a602 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -41,6 +41,8 @@ If you depend on these features, please raise your voice in
 * mitmproxy's command line interface now supports Windows (@mhils)
 * The `clientconnect`, `clientdisconnect`, `serverconnect`, `serverdisconnect`, and `log`
   events have been replaced with new events, see addon documentation for details (@mhils)
+* Contentviews now implement `render_priority` instead of `should_render`, allowing more specialization (@mhils)
+* Automatic JSON view mode when `+json` suffix in content type (@kam800)
 * Use pyca/cryptography to generate certificates, not pyOpenSSL (@mhils)
 * Remove the legacy protocol stack (@Kriechi)
 * Remove all deprecated pathod and pathoc tools and modules (@Kriechi)
diff --git a/examples/addons/contentview.py b/examples/addons/contentview.py
index 0b24daf77..319560202 100644
--- a/examples/addons/contentview.py
+++ b/examples/addons/contentview.py
@@ -5,16 +5,32 @@ This example shows how one can add a custom contentview to mitmproxy,
 which is used to pretty-print HTTP bodies for example.
 The content view API is explained in the mitmproxy.contentviews module.
 """
-from mitmproxy import contentviews
+from typing import Optional
+
+from mitmproxy import contentviews, flow
+from mitmproxy.net import http
 
 
 class ViewSwapCase(contentviews.View):
     name = "swapcase"
-    content_types = ["text/plain"]
 
     def __call__(self, data, **metadata) -> contentviews.TViewResult:
         return "case-swapped text", contentviews.format_text(data.swapcase())
 
+    def render_priority(
+        self,
+        data: bytes,
+        *,
+        content_type: Optional[str] = None,
+        flow: Optional[flow.Flow] = None,
+        http_message: Optional[http.Message] = None,
+        **unknown_metadata,
+    ) -> float:
+        if content_type == "text/plain":
+            return 1
+        else:
+            return 0
+
 
 view = ViewSwapCase()
 
diff --git a/mitmproxy/addons/dumper.py b/mitmproxy/addons/dumper.py
index 70f2ed23c..55cbe088d 100644
--- a/mitmproxy/addons/dumper.py
+++ b/mitmproxy/addons/dumper.py
@@ -1,19 +1,20 @@
 import itertools
 import shutil
 import sys
-from typing import Optional, TextIO
+from typing import Optional, TextIO, Union
 
 import click
 
 from mitmproxy import contentviews
 from mitmproxy import ctx
-from mitmproxy import flow
 from mitmproxy import exceptions
 from mitmproxy import flowfilter
 from mitmproxy import http
 from mitmproxy.net import http as net_http
+from mitmproxy.tcp import TCPFlow, TCPMessage
 from mitmproxy.utils import human
 from mitmproxy.utils import strutils
+from mitmproxy.websocket import WebSocketFlow, WebSocketMessage
 
 
 def indent(n: int, text: str) -> str:
@@ -94,7 +95,11 @@ class Dumper:
         self.echo(click.style("--- HTTP Trailers", fg="magenta"), ident=4)
         self._echo_headers(trailers)
 
-    def _echo_message(self, message, flow: flow.Flow):
+    def _echo_message(
+        self,
+        message: Union[net_http.Message, TCPMessage, WebSocketMessage],
+        flow: Union[http.HTTPFlow, TCPFlow, WebSocketFlow]
+    ):
         _, lines, error = contentviews.get_message_content_view(
             ctx.options.dumper_default_contentview,
             message,
@@ -165,8 +170,8 @@ class Dumper:
 
         http_version = ""
         if (
-                flow.request.http_version not in ("HTTP/1.1", "HTTP/1.0")
-                or flow.request.http_version != getattr(flow.response, "http_version", "HTTP/1.1")
+            not (flow.request.is_http10 or flow.request.is_http11)
+            or flow.request.http_version != getattr(flow.response, "http_version", "HTTP/1.1")
         ):
             # Hide version for h1 <-> h1 connections.
             http_version = " " + flow.request.http_version
@@ -215,8 +220,8 @@ class Dumper:
 
         http_version = ""
         if (
-                flow.response.http_version not in ("HTTP/1.1", "HTTP/1.0")
-                or flow.request.http_version != flow.response.http_version
+            not (flow.response.is_http10 or flow.response.is_http11)
+            or flow.request.http_version != flow.response.http_version
         ):
             # Hide version for h1 <-> h1 connections.
             http_version = f"{flow.response.http_version} "
@@ -226,7 +231,8 @@ class Dumper:
             # This aligns the HTTP response code with the HTTP request method:
             # 127.0.0.1:59519: GET http://example.com/
             #               << 304 Not Modified 0b
-            pad = max(0, len(human.format_address(flow.client_conn.peername)) - (2 + len(http_version) + len(replay_str)))
+            pad = max(0,
+                      len(human.format_address(flow.client_conn.peername)) - (2 + len(http_version) + len(replay_str)))
             arrows = " " * pad + arrows
 
         self.echo(f"{replay}{arrows} {http_version}{code} {reason} {size}")
diff --git a/mitmproxy/contentviews/__init__.py b/mitmproxy/contentviews/__init__.py
index 893e84fe5..dbe785fe5 100644
--- a/mitmproxy/contentviews/__init__.py
+++ b/mitmproxy/contentviews/__init__.py
@@ -3,21 +3,19 @@ Mitmproxy Content Views
 =======================
 
 mitmproxy includes a set of content views which can be used to
-format/decode/highlight data. While they are currently used for HTTP message
-bodies only, the may be used in other contexts in the future, e.g. to decode
-protobuf messages sent as WebSocket frames.
+format/decode/highlight data. While they are mostly used for HTTP message
+bodies, the may be used in other contexts, e.g. to decode WebSocket messages.
 
 Thus, the View API is very minimalistic. The only arguments are `data` and
 `**metadata`, where `data` is the actual content (as bytes). The contents on
-metadata depend on the protocol in use. For HTTP, the message headers and
-message trailers are passed as the ``headers`` and ``trailers`` keyword
-argument. For HTTP requests, the query parameters are passed as the ``query``
-keyword argument.
+metadata depend on the protocol in use. Known attributes can be found in
+`base.View`.
 """
 import traceback
-from typing import Dict, Optional  # noqa
-from typing import List  # noqa
+from typing import List, Union
+from typing import Optional
 
+from mitmproxy import flow
 from mitmproxy.net import http
 from mitmproxy.utils import strutils
 from . import (
@@ -25,9 +23,11 @@ from . import (
     urlencoded, multipart, image, query, protobuf, msgpack
 )
 from .base import View, KEY_MAX, format_text, format_dict, TViewResult
+from ..http import HTTPFlow
+from ..tcp import TCPMessage, TCPFlow
+from ..websocket import WebSocketMessage, WebSocketFlow
 
 views: List[View] = []
-content_types_map: Dict[str, List[View]] = {}
 
 
 def get(name: str) -> Optional[View]:
@@ -45,19 +45,8 @@ def add(view: View) -> None:
 
     views.append(view)
 
-    for ct in view.content_types:
-        l = content_types_map.setdefault(ct, [])
-        l.append(view)
-
 
 def remove(view: View) -> None:
-    for ct in view.content_types:
-        l = content_types_map.setdefault(ct, [])
-        l.remove(view)
-
-        if not len(l):
-            del content_types_map[ct]
-
     views.remove(view)
 
 
@@ -75,16 +64,24 @@ def safe_to_print(lines, encoding="utf8"):
         yield clean_line
 
 
-def get_message_content_view(viewname, message, flow):
+def get_message_content_view(
+    viewname: str,
+    message: Union[http.Message, TCPMessage, WebSocketMessage],
+    flow: Union[HTTPFlow, TCPFlow, WebSocketFlow],
+):
     """
     Like get_content_view, but also handles message encoding.
     """
     viewmode = get(viewname)
     if not viewmode:
         viewmode = get("auto")
+    assert viewmode
+
+    content: Optional[bytes]
     try:
-        content = message.content
+        content = message.content  # type: ignore
     except ValueError:
+        assert isinstance(message, http.Message)
         content = message.raw_content
         enc = "[cannot decode]"
     else:
@@ -93,22 +90,24 @@ def get_message_content_view(viewname, message, flow):
                 message.headers.get("content-encoding")
             )
         else:
-            enc = None
+            enc = ""
 
     if content is None:
         return "", iter([[("error", "content missing")]]), None
 
-    metadata = {}
-    if isinstance(message, http.Request):
-        metadata["query"] = message.query
+    content_type = None
+    http_message = None
     if isinstance(message, http.Message):
-        metadata["headers"] = message.headers
-        metadata["trailers"] = message.trailers
-    metadata["message"] = message
-    metadata["flow"] = flow
+        http_message = message
+        if ctype := message.headers.get("content-type"):
+            if ct := http.parse_content_type(ctype):
+                content_type = f"{ct[0]}/{ct[1]}"
 
     description, lines, error = get_content_view(
-        viewmode, content, **metadata
+        viewmode, content,
+        content_type=content_type,
+        flow=flow,
+        http_message=http_message,
     )
 
     if enc:
@@ -117,7 +116,11 @@ def get_message_content_view(viewname, message, flow):
     return description, lines, error
 
 
-def get_tcp_content_view(viewname: str, data: bytes):
+def get_tcp_content_view(
+    viewname: str,
+    data: bytes,
+    flow: TCPFlow,
+):
     viewmode = get(viewname)
     if not viewmode:
         viewmode = get("auto")
@@ -125,12 +128,19 @@ def get_tcp_content_view(viewname: str, data: bytes):
     # https://github.com/mitmproxy/mitmproxy/pull/3970#issuecomment-623024447
     assert viewmode
 
-    description, lines, error = get_content_view(viewmode, data)
+    description, lines, error = get_content_view(viewmode, data, flow=flow)
 
     return description, lines, error
 
 
-def get_content_view(viewmode: View, data: bytes, **metadata):
+def get_content_view(
+    viewmode: View,
+    data: bytes,
+    *,
+    content_type: Optional[str] = None,
+    flow: Optional[flow.Flow] = None,
+    http_message: Optional[http.Message] = None,
+):
     """
         Args:
             viewmode: the view to use.
@@ -143,9 +153,11 @@ def get_content_view(viewmode: View, data: bytes, **metadata):
             In contrast to calling the views directly, text is always safe-to-print unicode.
     """
     try:
-        ret = viewmode(data, **metadata)
+        ret = viewmode(data, content_type=content_type, flow=flow, http_message=http_message)
         if ret is None:
-            ret = "Couldn't parse: falling back to Raw", get("Raw")(data, **metadata)[1]
+            ret = "Couldn't parse: falling back to Raw", get("Raw")(
+                data, content_type=content_type, flow=flow, http_message=http_message
+            )[1]
         desc, content = ret
         error = None
     # Third-party viewers can fail in unexpected ways...
@@ -153,11 +165,8 @@ def get_content_view(viewmode: View, data: bytes, **metadata):
         desc = "Couldn't parse: falling back to Raw"
         raw = get("Raw")
         assert raw
-        content = raw(data, **metadata)[1]
-        error = "{} Content viewer failed: \n{}".format(
-            getattr(viewmode, "name"),
-            traceback.format_exc()
-        )
+        content = raw(data, content_type=content_type, flow=flow, http_message=http_message)[1]
+        error = f"{getattr(viewmode, 'name')} content viewer failed: \n{traceback.format_exc()}"
 
     return desc, safe_to_print(content), error
 
diff --git a/mitmproxy/contentviews/auto.py b/mitmproxy/contentviews/auto.py
index 05ef99c69..0dc75b65a 100644
--- a/mitmproxy/contentviews/auto.py
+++ b/mitmproxy/contentviews/auto.py
@@ -1,6 +1,4 @@
 from mitmproxy import contentviews
-from mitmproxy.net import http
-from mitmproxy.utils import strutils
 from . import base
 
 
@@ -8,21 +6,15 @@ class ViewAuto(base.View):
     name = "Auto"
 
     def __call__(self, data, **metadata):
-        headers = metadata.get("headers", {})
-        ctype = headers.get("content-type")
-        if data and ctype:
-            ct = http.parse_content_type(ctype) if ctype else None
-            ct = "{}/{}".format(ct[0], ct[1])
-            if ct in contentviews.content_types_map:
-                return contentviews.content_types_map[ct][0](data, **metadata)
-            elif strutils.is_xml(data):
-                return contentviews.get("XML/HTML")(data, **metadata)
-            elif ct.startswith("image/"):
-                return contentviews.get("Image")(data, **metadata)
-        if metadata.get("query"):
-            return contentviews.get("Query")(data, **metadata)
-        if data and strutils.is_mostly_bin(data):
-            return contentviews.get("Hex")(data)
-        if not data:
+        # TODO: The auto view has little justification now that views implement render_priority,
+        # but we keep it around for now to not touch more parts.
+        priority, view = max(
+            (v.render_priority(data, **metadata), v)
+            for v in contentviews.views
+        )
+        if priority == 0 and not data:
             return "No content", []
-        return contentviews.get("Raw")(data)
+        return view(data, **metadata)
+
+    def render_priority(self, data: bytes, **metadata) -> float:
+        return -1  # don't recurse.
diff --git a/mitmproxy/contentviews/base.py b/mitmproxy/contentviews/base.py
index 81f2e4879..aa84c4a17 100644
--- a/mitmproxy/contentviews/base.py
+++ b/mitmproxy/contentviews/base.py
@@ -1,5 +1,9 @@
 # Default view cutoff *in lines*
 import typing
+from abc import ABC, abstractmethod
+
+from mitmproxy import flow
+from mitmproxy.net import http
 
 KEY_MAX = 30
 
@@ -8,37 +12,62 @@ TViewLine = typing.List[typing.Tuple[str, TTextType]]
 TViewResult = typing.Tuple[str, typing.Iterator[TViewLine]]
 
 
-class View:
+class View(ABC):
     name: typing.ClassVar[str]
-    content_types: typing.ClassVar[typing.List[str]] = []
 
-    def __call__(self, data: bytes, **metadata) -> TViewResult:
+    @abstractmethod
+    def __call__(
+        self,
+        data: bytes,
+        *,
+        content_type: typing.Optional[str] = None,
+        flow: typing.Optional[flow.Flow] = None,
+        http_message: typing.Optional[http.Message] = None,
+        **unknown_metadata,
+    ) -> TViewResult:
         """
         Transform raw data into human-readable output.
 
-        Args:
-            data: the data to decode/format.
-            metadata: optional keyword-only arguments for metadata. Implementations must not
-                rely on a given argument being present.
+        Returns a (description, content generator) tuple.
+        The content generator yields lists of (style, text) tuples, where each list represents
+        a single line. ``text`` is a unfiltered string which may need to be escaped,
+        depending on the used output. For example, it may contain terminal control sequences
+        or unfiltered HTML.
 
-        Returns:
-            A (description, content generator) tuple.
+        Except for `data`, implementations must not rely on any given argument to be present.
+        To ensure compatibility with future mitmproxy versions, unknown keyword arguments should be ignored.
 
-            The content generator yields lists of (style, text) tuples, where each list represents
-            a single line. ``text`` is a unfiltered byte string which may need to be escaped,
-            depending on the used output.
-
-        Caveats:
-            The content generator must not yield tuples of tuples,
-            because urwid cannot process that. You have to yield a *list* of tuples per line.
+        The content generator must not yield tuples of tuples, because urwid cannot process that.
+        You have to yield a *list* of tuples per line.
         """
         raise NotImplementedError()  # pragma: no cover
 
+    def render_priority(
+        self,
+        data: bytes,
+        *,
+        content_type: typing.Optional[str] = None,
+        flow: typing.Optional[flow.Flow] = None,
+        http_message: typing.Optional[http.Message] = None,
+        **unknown_metadata,
+    ) -> float:
+        """
+        Return the priority of this view for rendering `data`.
+        If no particular view is chosen by the user, the view with the highest priority is selected.
+
+        Except for `data`, implementations must not rely on any given argument to be present.
+        To ensure compatibility with future mitmproxy versions, unknown keyword arguments should be ignored.
+        """
+        return 0
+
+    def __lt__(self, other):
+        assert isinstance(other, View)
+        return self.name.__lt__(other.name)
+
 
 def format_pairs(
-        items: typing.Iterable[typing.Tuple[TTextType, TTextType]]
+    items: typing.Iterable[typing.Tuple[TTextType, TTextType]]
 ) -> typing.Iterator[TViewLine]:
-
     """
     Helper function that accepts a list of (k,v) pairs into a list of
     [
@@ -67,7 +96,7 @@ def format_pairs(
 
 
 def format_dict(
-        d: typing.Mapping[TTextType, TTextType]
+    d: typing.Mapping[TTextType, TTextType]
 ) -> typing.Iterator[TViewLine]:
     """
     Helper function that transforms the given dictionary into a list of
diff --git a/mitmproxy/contentviews/css.py b/mitmproxy/contentviews/css.py
index 44b33761e..cc162eb4a 100644
--- a/mitmproxy/contentviews/css.py
+++ b/mitmproxy/contentviews/css.py
@@ -1,5 +1,6 @@
 import re
 import time
+from typing import Optional
 
 from mitmproxy.contentviews import base
 from mitmproxy.utils import strutils
@@ -50,15 +51,15 @@ def beautify(data: str, indent: str = "    "):
 
 class ViewCSS(base.View):
     name = "CSS"
-    content_types = [
-        "text/css"
-    ]
 
     def __call__(self, data, **metadata):
         data = data.decode("utf8", "surrogateescape")
         beautified = beautify(data)
         return "CSS", base.format_text(beautified)
 
+    def render_priority(self, data: bytes, *, content_type: Optional[str] = None, **metadata) -> float:
+        return float(content_type == "text/css")
+
 
 if __name__ == "__main__":  # pragma: no cover
     with open("../tools/web/static/vendor.css") as f:
diff --git a/mitmproxy/contentviews/hex.py b/mitmproxy/contentviews/hex.py
index f88bf80c5..cca30f0ff 100644
--- a/mitmproxy/contentviews/hex.py
+++ b/mitmproxy/contentviews/hex.py
@@ -16,3 +16,6 @@ class ViewHex(base.View):
 
     def __call__(self, data, **metadata):
         return "Hex", self._format(data)
+
+    def render_priority(self, data: bytes, **metadata) -> float:
+        return 0.2 * strutils.is_mostly_bin(data)
diff --git a/mitmproxy/contentviews/image/view.py b/mitmproxy/contentviews/image/view.py
index 4b5fd149f..9ab515c8f 100644
--- a/mitmproxy/contentviews/image/view.py
+++ b/mitmproxy/contentviews/image/view.py
@@ -1,4 +1,5 @@
 import imghdr
+from typing import Optional
 
 from mitmproxy.contentviews import base
 from mitmproxy.coretypes import multidict
@@ -16,16 +17,6 @@ imghdr.tests.append(test_ico)
 class ViewImage(base.View):
     name = "Image"
 
-    # there is also a fallback in the auto view for image/*.
-    content_types = [
-        "image/png",
-        "image/jpeg",
-        "image/gif",
-        "image/vnd.microsoft.icon",
-        "image/x-icon",
-        "image/webp",
-    ]
-
     def __call__(self, data, **metadata):
         image_type = imghdr.what('', h=data)
         if image_type == 'png':
@@ -45,3 +36,10 @@ class ViewImage(base.View):
         else:
             view_name = "Unknown Image"
         return view_name, base.format_dict(multidict.MultiDict(image_metadata))
+
+    def render_priority(self, data: bytes, *, content_type: Optional[str] = None, **metadata) -> float:
+        return float(bool(
+            content_type
+            and content_type.startswith("image/")
+            and content_type != "image/svg+xml"
+        ))
diff --git a/mitmproxy/contentviews/javascript.py b/mitmproxy/contentviews/javascript.py
index b5f09150f..bad7fc2a8 100644
--- a/mitmproxy/contentviews/javascript.py
+++ b/mitmproxy/contentviews/javascript.py
@@ -1,5 +1,6 @@
 import io
 import re
+from typing import Optional
 
 from mitmproxy.utils import strutils
 from mitmproxy.contentviews import base
@@ -46,13 +47,16 @@ def beautify(data):
 
 class ViewJavaScript(base.View):
     name = "JavaScript"
-    content_types = [
+    __content_types = (
         "application/x-javascript",
         "application/javascript",
         "text/javascript"
-    ]
+    )
 
     def __call__(self, data, **metadata):
         data = data.decode("utf-8", "replace")
         res = beautify(data)
         return "JavaScript", base.format_text(res)
+
+    def render_priority(self, data: bytes, *, content_type: Optional[str] = None, **metadata) -> float:
+        return float(content_type in self.__content_types)
diff --git a/mitmproxy/contentviews/json.py b/mitmproxy/contentviews/json.py
index a5a7d03b4..2b3891541 100644
--- a/mitmproxy/contentviews/json.py
+++ b/mitmproxy/contentviews/json.py
@@ -38,13 +38,18 @@ def format_json(data: typing.Any) -> typing.Iterator[base.TViewLine]:
 
 class ViewJSON(base.View):
     name = "JSON"
-    content_types = [
-        "application/json",
-        "application/json-rpc",
-        "application/vnd.api+json"
-    ]
 
     def __call__(self, data, **metadata):
         data = parse_json(data)
         if data is not PARSE_ERROR:
             return "JSON", format_json(data)
+
+    def render_priority(self, data: bytes, *, content_type: typing.Optional[str] = None, **metadata) -> float:
+        if content_type in (
+            "application/json",
+            "application/json-rpc",
+        ):
+            return 1
+        if content_type and content_type.startswith("application/") and content_type.endswith("+json"):
+            return 1
+        return 0
diff --git a/mitmproxy/contentviews/msgpack.py b/mitmproxy/contentviews/msgpack.py
index fec1f60c2..975440f41 100644
--- a/mitmproxy/contentviews/msgpack.py
+++ b/mitmproxy/contentviews/msgpack.py
@@ -39,12 +39,15 @@ def format_msgpack(data):
 
 class ViewMsgPack(base.View):
     name = "MsgPack"
-    content_types = [
+    __content_types = (
         "application/msgpack",
         "application/x-msgpack",
-    ]
+    )
 
     def __call__(self, data, **metadata):
         data = parse_msgpack(data)
         if data is not PARSE_ERROR:
             return "MsgPack", format_msgpack(data)
+
+    def render_priority(self, data: bytes, *, content_type: typing.Optional[str] = None, **metadata) -> float:
+        return float(content_type in self.__content_types)
diff --git a/mitmproxy/contentviews/multipart.py b/mitmproxy/contentviews/multipart.py
index 90b60030b..8a01e2e7f 100644
--- a/mitmproxy/contentviews/multipart.py
+++ b/mitmproxy/contentviews/multipart.py
@@ -1,19 +1,24 @@
-from mitmproxy.net import http
+from typing import Optional
+
 from mitmproxy.coretypes import multidict
+from mitmproxy.net import http
 from . import base
 
 
 class ViewMultipart(base.View):
     name = "Multipart Form"
-    content_types = ["multipart/form-data"]
 
     @staticmethod
     def _format(v):
         yield [("highlight", "Form data:\n")]
         yield from base.format_dict(multidict.MultiDict(v))
 
-    def __call__(self, data, **metadata):
-        headers = metadata.get("headers", {})
-        v = http.multipart.decode(headers, data)
+    def __call__(self, data: bytes, content_type: Optional[str] = None, **metadata):
+        if content_type is None:
+            return
+        v = http.multipart.decode(content_type, data)
         if v:
             return "Multipart form", self._format(v)
+
+    def render_priority(self, data: bytes, *, content_type: Optional[str] = None, **metadata) -> float:
+        return float(content_type == "multipart/form-data")
diff --git a/mitmproxy/contentviews/protobuf.py b/mitmproxy/contentviews/protobuf.py
index 50f8dcede..c470d077c 100644
--- a/mitmproxy/contentviews/protobuf.py
+++ b/mitmproxy/contentviews/protobuf.py
@@ -1,4 +1,5 @@
 import io
+from typing import Optional
 
 from kaitaistruct import KaitaiStream
 from . import base
@@ -66,7 +67,7 @@ class ViewProtobuf(base.View):
     """
 
     name = "Protocol Buffer"
-    content_types = [
+    __content_types = [
         "application/x-protobuf",
         "application/x-protobuffer",
     ]
@@ -77,3 +78,6 @@ class ViewProtobuf(base.View):
             raise ValueError("Failed to parse input.")
 
         return "Protobuf", base.format_text(decoded)
+
+    def render_priority(self, data: bytes, *, content_type: Optional[str] = None, **metadata) -> float:
+        return float(content_type in self.__content_types)
diff --git a/mitmproxy/contentviews/query.py b/mitmproxy/contentviews/query.py
index 0f74ea2f4..01cca6f6b 100644
--- a/mitmproxy/contentviews/query.py
+++ b/mitmproxy/contentviews/query.py
@@ -1,14 +1,18 @@
-from typing import List  # noqa
+from typing import Optional
 
 from . import base
+from ..net import http
 
 
 class ViewQuery(base.View):
     name = "Query"
 
-    def __call__(self, data, **metadata):
-        query = metadata.get("query")
+    def __call__(self, data: bytes, http_message: Optional[http.Message] = None, **metadata):
+        query = getattr(http_message, "query", None)
         if query:
             return "Query", base.format_pairs(query.items(multi=True))
         else:
             return "Query", base.format_text("")
+
+    def render_priority(self, data: bytes, *, http_message: Optional[http.Message] = None, **metadata) -> float:
+        return 0.3 * float(bool(getattr(http_message, "query", False)))
diff --git a/mitmproxy/contentviews/raw.py b/mitmproxy/contentviews/raw.py
index 300e70bb1..248021403 100644
--- a/mitmproxy/contentviews/raw.py
+++ b/mitmproxy/contentviews/raw.py
@@ -9,3 +9,6 @@ class ViewRaw(base.View):
 
     def __call__(self, data, **metadata):
         return "Raw", base.format_text(strutils.bytes_to_escaped_str(data, True))
+
+    def render_priority(self, data: bytes, **metadata) -> float:
+        return 0.1 * float(bool(data))
diff --git a/mitmproxy/contentviews/urlencoded.py b/mitmproxy/contentviews/urlencoded.py
index e35bbdb7a..22b1ba21b 100644
--- a/mitmproxy/contentviews/urlencoded.py
+++ b/mitmproxy/contentviews/urlencoded.py
@@ -1,10 +1,11 @@
+from typing import Optional
+
 from mitmproxy.net.http import url
 from . import base
 
 
 class ViewURLEncoded(base.View):
     name = "URL-encoded"
-    content_types = ["application/x-www-form-urlencoded"]
 
     def __call__(self, data, **metadata):
         try:
@@ -13,3 +14,6 @@ class ViewURLEncoded(base.View):
             return None
         d = url.decode(data)
         return "URLEncoded form", base.format_pairs(d)
+
+    def render_priority(self, data: bytes, *, content_type: Optional[str] = None, **metadata) -> float:
+        return float(content_type == "application/x-www-form-urlencoded")
diff --git a/mitmproxy/contentviews/wbxml.py b/mitmproxy/contentviews/wbxml.py
index b33f4ce89..c13124f33 100644
--- a/mitmproxy/contentviews/wbxml.py
+++ b/mitmproxy/contentviews/wbxml.py
@@ -1,13 +1,15 @@
+from typing import Optional
+
 from mitmproxy.contrib.wbxml import ASCommandResponse
 from . import base
 
 
 class ViewWBXML(base.View):
     name = "WBXML"
-    content_types = [
+    __content_types = (
         "application/vnd.wap.wbxml",
         "application/vnd.ms-sync.wbxml"
-    ]
+    )
 
     def __call__(self, data, **metadata):
         try:
@@ -17,3 +19,6 @@ class ViewWBXML(base.View):
                 return "WBXML", base.format_text(parsedContent)
         except:
             return None
+
+    def render_priority(self, data: bytes, *, content_type: Optional[str] = None, **metadata) -> float:
+        return float(content_type in self.__content_types)
diff --git a/mitmproxy/contentviews/xml_html.py b/mitmproxy/contentviews/xml_html.py
index f2fa47cb1..509cb55f2 100644
--- a/mitmproxy/contentviews/xml_html.py
+++ b/mitmproxy/contentviews/xml_html.py
@@ -4,7 +4,7 @@ import textwrap
 from typing import Iterable, Optional
 
 from mitmproxy.contentviews import base
-from mitmproxy.utils import sliding_window
+from mitmproxy.utils import sliding_window, strutils
 
 """
 A custom XML/HTML prettifier. Compared to other prettifiers, its main features are:
@@ -214,7 +214,7 @@ def format_xml(tokens: Iterable[Token]) -> str:
 
 class ViewXmlHtml(base.View):
     name = "XML/HTML"
-    content_types = ["text/xml", "text/html"]
+    __content_types = ("text/xml", "text/html")
 
     def __call__(self, data, **metadata):
         # TODO:
@@ -233,3 +233,10 @@ class ViewXmlHtml(base.View):
         else:
             t = "XML"
         return t, pretty
+
+    def render_priority(self, data: bytes, *, content_type: Optional[str] = None, **metadata) -> float:
+        if content_type in self.__content_types:
+            return 1
+        elif strutils.is_xml(data):
+            return 0.4
+        return float(content_type in self.__content_types)
diff --git a/mitmproxy/hooks.py b/mitmproxy/hooks.py
index 95246f905..77b6d207f 100644
--- a/mitmproxy/hooks.py
+++ b/mitmproxy/hooks.py
@@ -1,4 +1,5 @@
 import re
+import warnings
 from dataclasses import dataclass, is_dataclass, fields
 from typing import ClassVar, Any, Dict, Type, Set, List, TYPE_CHECKING, Sequence
 
@@ -32,7 +33,7 @@ class Hook:
             cls.name = re.sub('(?!^)([A-Z]+)', r'_\1', name).lower()
         if cls.name in all_hooks:
             other = all_hooks[cls.name]
-            raise RuntimeError(f"Two conflicting event classes for {cls.name}: {cls} and {other}")
+            warnings.warn(f"Two conflicting event classes for {cls.name}: {cls} and {other}", RuntimeWarning)
         if cls.name == "":
             return  # don't register Hook class.
         all_hooks[cls.name] = cls
diff --git a/mitmproxy/http.py b/mitmproxy/http.py
index c0e6ae356..a41fb6f9b 100644
--- a/mitmproxy/http.py
+++ b/mitmproxy/http.py
@@ -65,9 +65,9 @@ class HTTPFlow(flow.Flow):
 
 
 def make_error_response(
-        status_code: int,
-        message: str = "",
-        headers: Optional[http.Headers] = None,
+    status_code: int,
+    message: str = "",
+    headers: Optional[http.Headers] = None,
 ) -> http.Response:
     body: bytes = """
         <html>
diff --git a/mitmproxy/master.py b/mitmproxy/master.py
index 8be976dda..4f4910b16 100644
--- a/mitmproxy/master.py
+++ b/mitmproxy/master.py
@@ -69,7 +69,7 @@ class Master:
             print(exc, file=sys.stderr)
             print("mitmproxy has crashed!", file=sys.stderr)
             print("Please lodge a bug report at:", file=sys.stderr)
-            print("\thttps://github.com/mitmproxy/mitmproxy", file=sys.stderr)
+            print("\thttps://github.com/mitmproxy/mitmproxy/issues", file=sys.stderr)
 
         self.addons.trigger(hooks.DoneHook())
 
diff --git a/mitmproxy/net/http/multipart.py b/mitmproxy/net/http/multipart.py
index 4edf76acd..bfb9f6139 100644
--- a/mitmproxy/net/http/multipart.py
+++ b/mitmproxy/net/http/multipart.py
@@ -1,11 +1,12 @@
-import re
 import mimetypes
+import re
+from typing import Tuple, List, Optional
 from urllib.parse import quote
+
 from mitmproxy.net.http import headers
 
 
 def encode(head, l):
-
     k = head.get("content-type")
     if k:
         k = headers.parse_content_type(k)
@@ -38,17 +39,16 @@ def encode(head, l):
             return temp
 
 
-def decode(hdrs, content):
+def decode(content_type: Optional[str], content: bytes) -> List[Tuple[bytes, bytes]]:
     """
         Takes a multipart boundary encoded string and returns list of (key, value) tuples.
     """
-    v = hdrs.get("content-type")
-    if v:
-        v = headers.parse_content_type(v)
-        if not v:
+    if content_type:
+        ct = headers.parse_content_type(content_type)
+        if not ct:
             return []
         try:
-            boundary = v[2]["boundary"].encode("ascii")
+            boundary = ct[2]["boundary"].encode("ascii")
         except (KeyError, UnicodeError):
             return []
 
diff --git a/mitmproxy/net/http/request.py b/mitmproxy/net/http/request.py
index 3f9595520..e8173493c 100644
--- a/mitmproxy/net/http/request.py
+++ b/mitmproxy/net/http/request.py
@@ -449,7 +449,7 @@ class Request(message.Message):
         is_valid_content_type = "multipart/form-data" in self.headers.get("content-type", "").lower()
         if is_valid_content_type:
             try:
-                return multipart.decode(self.headers, self.content)
+                return multipart.decode(self.headers.get("content-type"), self.content)
             except ValueError:
                 pass
         return ()
diff --git a/mitmproxy/proxy/context.py b/mitmproxy/proxy/context.py
index a2e1f6f32..3decd318d 100644
--- a/mitmproxy/proxy/context.py
+++ b/mitmproxy/proxy/context.py
@@ -4,6 +4,7 @@ from abc import ABCMeta
 from enum import Flag
 from typing import List, Literal, Optional, Sequence, Tuple, Union, TYPE_CHECKING
 
+import mitmproxy
 from mitmproxy import certs
 from mitmproxy.coretypes import serializable
 from mitmproxy.net import server_spec
diff --git a/mitmproxy/proxy/events.py b/mitmproxy/proxy/events.py
index 1f219ea2e..7666d1985 100644
--- a/mitmproxy/proxy/events.py
+++ b/mitmproxy/proxy/events.py
@@ -5,6 +5,7 @@ The counterpart to events are commands.
 """
 import socket
 import typing
+import warnings
 from dataclasses import dataclass, is_dataclass
 
 from mitmproxy.proxy import commands
@@ -78,7 +79,7 @@ class CommandCompleted(Event):
             raise RuntimeError(f"{command_cls} needs a properly annotated command attribute.")
         if command_cls in command_reply_subclasses:
             other = command_reply_subclasses[command_cls]
-            raise RuntimeError(f"Two conflicting subclasses for {command_cls}: {cls} and {other}")
+            warnings.warn(f"Two conflicting subclasses for {command_cls}: {cls} and {other}", RuntimeWarning)
         command_reply_subclasses[command_cls] = cls
 
     def __repr__(self):
diff --git a/mitmproxy/proxy/layer.py b/mitmproxy/proxy/layer.py
index 2fbbc7d41..6798557de 100644
--- a/mitmproxy/proxy/layer.py
+++ b/mitmproxy/proxy/layer.py
@@ -222,7 +222,7 @@ class NextLayer(Layer):
             #  3. Some layers may however still have a reference to the old .handle_event.
             #     ._handle is just an optimization to reduce the callstack in these cases.
             self.handle_event = self.layer.handle_event
-            self._handle_event = self.layer._handle_event
+            self._handle_event = self.layer.handle_event
             self._handle = self.layer.handle_event
 
     # Utility methods for whoever decides what the next layer is going to be.
diff --git a/mitmproxy/tools/console/flowview.py b/mitmproxy/tools/console/flowview.py
index 3985697c2..7d8484022 100644
--- a/mitmproxy/tools/console/flowview.py
+++ b/mitmproxy/tools/console/flowview.py
@@ -152,7 +152,7 @@ class FlowDetails(tabs.Tabs):
 
         from_client = flow.messages[0].from_client
         for m in messages:
-            _, lines, _ = contentviews.get_tcp_content_view(viewmode, m)
+            _, lines, _ = contentviews.get_tcp_content_view(viewmode, m, flow)
 
             for line in lines:
                 if from_client:
diff --git a/mitmproxy/tools/web/static_viewer.py b/mitmproxy/tools/web/static_viewer.py
index 31d4b3c00..7fa87e10a 100644
--- a/mitmproxy/tools/web/static_viewer.py
+++ b/mitmproxy/tools/web/static_viewer.py
@@ -5,7 +5,7 @@ import shutil
 import time
 import typing
 
-from mitmproxy import contentviews
+from mitmproxy import contentviews, http
 from mitmproxy import ctx
 from mitmproxy import flowfilter
 from mitmproxy import io, flow
@@ -49,6 +49,7 @@ def save_flows(path: pathlib.Path, flows: typing.Iterable[flow.Flow]) -> None:
 
 def save_flows_content(path: pathlib.Path, flows: typing.Iterable[flow.Flow]) -> None:
     for f in flows:
+        assert isinstance(f, http.HTTPFlow)
         for m in ('request', 'response'):
             message = getattr(f, m)
             message_path = path / "flows" / f.id / m
diff --git a/mitmproxy/utils/arg_check.py b/mitmproxy/utils/arg_check.py
index e7de8a703..4bb1f1812 100644
--- a/mitmproxy/utils/arg_check.py
+++ b/mitmproxy/utils/arg_check.py
@@ -156,7 +156,7 @@ def check():
 
     # Check for underscores in the options. Options always follow '--'.
     for argument in args:
-        underscoreParam = re.search('[-]{2}((.*?_)(.*?(\s|$)))+', argument)
+        underscoreParam = re.search(r'[-]{2}((.*?_)(.*?(\s|$)))+', argument)
         if underscoreParam is not None:
             print("{} uses underscores, please use hyphens {}".format(
                 argument,
diff --git a/mitmproxy/utils/strutils.py b/mitmproxy/utils/strutils.py
index 7329605f0..3debb2aa3 100644
--- a/mitmproxy/utils/strutils.py
+++ b/mitmproxy/utils/strutils.py
@@ -133,7 +133,11 @@ def is_mostly_bin(s: bytes) -> bool:
 
 
 def is_xml(s: bytes) -> bool:
-    return s.strip().startswith(b"<")
+    for char in s:
+        if char in (9, 10, 32):  # is space?
+            continue
+        return char == 60  # is a "<"?
+    return False
 
 
 def clean_hanging_newline(t):
diff --git a/setup.py b/setup.py
index b8a766f90..9d83017e0 100644
--- a/setup.py
+++ b/setup.py
@@ -97,7 +97,7 @@ setup(
             "pydivert>=2.0.3,<2.2",
         ],
         'dev': [
-            "hypothesis>=5.8,<6",
+            "hypothesis>=5.8,<6.1",
             "parver>=0.1,<2.0",
             "pytest-asyncio>=0.10.0,<0.14,!=0.14",
             "pytest-cov>=2.7.1,<3",
diff --git a/test/mitmproxy/contentviews/image/test_view.py b/test/mitmproxy/contentviews/image/test_view.py
index 84dffcc71..7abfeb3f4 100644
--- a/test/mitmproxy/contentviews/image/test_view.py
+++ b/test/mitmproxy/contentviews/image/test_view.py
@@ -15,3 +15,15 @@ def test_view_image(tdata):
             assert img.split(".")[-1].upper() in viewname
 
     assert v(b"flibble") == ('Unknown Image', [[('header', 'Image Format: '), ('text', 'unknown')]])
+
+
+def test_render_priority():
+    v = image.ViewImage()
+    assert v.render_priority(b"", content_type="image/png")
+    assert v.render_priority(b"", content_type="image/jpeg")
+    assert v.render_priority(b"", content_type="image/gif")
+    assert v.render_priority(b"", content_type="image/vnd.microsoft.icon")
+    assert v.render_priority(b"", content_type="image/x-icon")
+    assert v.render_priority(b"", content_type="image/webp")
+    assert v.render_priority(b"", content_type="image/future-unknown-format-42")
+    assert not v.render_priority(b"", content_type="image/svg+xml")
diff --git a/test/mitmproxy/contentviews/test_api.py b/test/mitmproxy/contentviews/test_api.py
index d10ffb67f..c943610b0 100644
--- a/test/mitmproxy/contentviews/test_api.py
+++ b/test/mitmproxy/contentviews/test_api.py
@@ -3,14 +3,18 @@ from unittest import mock
 import pytest
 
 from mitmproxy import contentviews
-from mitmproxy.net.http import Headers
 from mitmproxy.test import tflow
 from mitmproxy.test import tutils
 
 
 class TestContentView(contentviews.View):
     name = "test"
-    content_types = ["test/123"]
+
+    def __call__(self, *args, **kwargs):
+        pass
+
+    def should_render(self, content_type):
+        return content_type == "test/123"
 
 
 def test_add_remove():
@@ -38,7 +42,7 @@ def test_get_content_view():
     desc, lines, err = contentviews.get_content_view(
         contentviews.get("Auto"),
         b"[1, 2, 3]",
-        headers=Headers(content_type="application/json")
+        content_type="application/json",
     )
     assert desc == "JSON"
     assert list(lines)
diff --git a/test/mitmproxy/contentviews/test_auto.py b/test/mitmproxy/contentviews/test_auto.py
index cd888a2d0..459d839f0 100644
--- a/test/mitmproxy/contentviews/test_auto.py
+++ b/test/mitmproxy/contentviews/test_auto.py
@@ -1,6 +1,5 @@
 from mitmproxy.contentviews import auto
-from mitmproxy.net import http
-from mitmproxy.coretypes import multidict
+from mitmproxy.test import tflow
 from . import full_eval
 
 
@@ -8,37 +7,42 @@ def test_view_auto():
     v = full_eval(auto.ViewAuto())
     f = v(
         b"foo",
-        headers=http.Headers()
     )
     assert f[0] == "Raw"
 
     f = v(
         b"<html></html>",
-        headers=http.Headers(content_type="text/html")
+        content_type="text/html",
     )
     assert f[0] == "HTML"
 
     f = v(
         b"foo",
-        headers=http.Headers(content_type="text/flibble")
+        content_type="text/flibble",
     )
     assert f[0] == "Raw"
 
     f = v(
         b"<xml></xml>",
-        headers=http.Headers(content_type="text/flibble")
+        content_type="text/flibble",
     )
     assert f[0].startswith("XML")
 
     f = v(
         b"<svg></svg>",
-        headers=http.Headers(content_type="image/svg+xml")
+        content_type="image/svg+xml",
     )
     assert f[0].startswith("XML")
 
+    f = v(
+        b"{}",
+        content_type="application/acme+json",
+    )
+    assert f[0].startswith("JSON")
+
     f = v(
         b"verybinary",
-        headers=http.Headers(content_type="image/new-magic-image-format")
+        content_type="image/new-magic-image-format",
     )
     assert f[0] == "Unknown Image"
 
@@ -47,13 +51,14 @@ def test_view_auto():
 
     f = v(
         b"",
-        headers=http.Headers()
     )
     assert f[0] == "No content"
 
+    flow = tflow.tflow()
+    flow.request.query = [("foo", "bar")]
     f = v(
         b"",
-        headers=http.Headers(),
-        query=multidict.MultiDict([("foo", "bar")]),
+        flow=flow,
+        http_message=flow.request,
     )
     assert f[0] == "Query"
diff --git a/test/mitmproxy/contentviews/test_css.py b/test/mitmproxy/contentviews/test_css.py
index af1f776bf..2479b4722 100644
--- a/test/mitmproxy/contentviews/test_css.py
+++ b/test/mitmproxy/contentviews/test_css.py
@@ -37,3 +37,9 @@ def test_simple():
     assert v(b"console.log('not really css')") == (
         'CSS', [[('text', "console.log('not really css')")]]
     )
+
+
+def test_render_priority():
+    v = css.ViewCSS()
+    assert v.render_priority(b"", content_type="text/css")
+    assert not v.render_priority(b"", content_type="text/plain")
diff --git a/test/mitmproxy/contentviews/test_hex.py b/test/mitmproxy/contentviews/test_hex.py
index 4292007e8..90db4bd7c 100644
--- a/test/mitmproxy/contentviews/test_hex.py
+++ b/test/mitmproxy/contentviews/test_hex.py
@@ -5,3 +5,10 @@ from . import full_eval
 def test_view_hex():
     v = full_eval(hex.ViewHex())
     assert v(b"foo")
+
+
+def test_render_priority():
+    v = hex.ViewHex()
+    assert not v.render_priority(b"ascii")
+    assert v.render_priority(b"\xFF")
+    assert not v.render_priority(b"")
diff --git a/test/mitmproxy/contentviews/test_javascript.py b/test/mitmproxy/contentviews/test_javascript.py
index 8a1027978..823b7e12d 100644
--- a/test/mitmproxy/contentviews/test_javascript.py
+++ b/test/mitmproxy/contentviews/test_javascript.py
@@ -27,3 +27,11 @@ def test_format_xml(filename, tdata):
         expected = f.read()
     js = javascript.beautify(input)
     assert js == expected
+
+
+def test_render_priority():
+    v = javascript.ViewJavaScript()
+    assert v.render_priority(b"", content_type="application/x-javascript")
+    assert v.render_priority(b"", content_type="application/javascript")
+    assert v.render_priority(b"", content_type="text/javascript")
+    assert not v.render_priority(b"", content_type="text/plain")
diff --git a/test/mitmproxy/contentviews/test_json.py b/test/mitmproxy/contentviews/test_json.py
index 2b5bf86a1..ba14b5490 100644
--- a/test/mitmproxy/contentviews/test_json.py
+++ b/test/mitmproxy/contentviews/test_json.py
@@ -41,3 +41,12 @@ def test_view_json():
 def test_view_json_doesnt_crash(data):
     v = full_eval(json.ViewJSON())
     v(data)
+
+
+def test_render_priority():
+    v = json.ViewJSON()
+    assert v.render_priority(b"", content_type="application/json")
+    assert v.render_priority(b"", content_type="application/json-rpc")
+    assert v.render_priority(b"", content_type="application/vnd.api+json")
+    assert v.render_priority(b"", content_type="application/acme+json")
+    assert not v.render_priority(b"", content_type="text/plain")
diff --git a/test/mitmproxy/contentviews/test_msgpack.py b/test/mitmproxy/contentviews/test_msgpack.py
index d9ce81e80..cfc7e666c 100644
--- a/test/mitmproxy/contentviews/test_msgpack.py
+++ b/test/mitmproxy/contentviews/test_msgpack.py
@@ -44,3 +44,10 @@ def test_view_msgpack():
 def test_view_msgpack_doesnt_crash(data):
     v = full_eval(msgpack.ViewMsgPack())
     v(data)
+
+
+def test_render_priority():
+    v = msgpack.ViewMsgPack()
+    assert v.render_priority(b"", content_type="application/msgpack")
+    assert v.render_priority(b"", content_type="application/x-msgpack")
+    assert not v.render_priority(b"", content_type="text/plain")
diff --git a/test/mitmproxy/contentviews/test_multipart.py b/test/mitmproxy/contentviews/test_multipart.py
index 48a5ccc90..99b6042b5 100644
--- a/test/mitmproxy/contentviews/test_multipart.py
+++ b/test/mitmproxy/contentviews/test_multipart.py
@@ -1,5 +1,4 @@
 from mitmproxy.contentviews import multipart
-from mitmproxy.net import http
 from . import full_eval
 
 
@@ -12,14 +11,16 @@ Content-Disposition: form-data; name="submit-name"
 Larry
 --AaB03x
         """.strip()
-    h = http.Headers(content_type="multipart/form-data; boundary=AaB03x")
-    assert view(v, headers=h)
+    assert view(v, content_type="multipart/form-data; boundary=AaB03x")
 
-    h = http.Headers()
-    assert not view(v, headers=h)
+    assert not view(v)
 
-    h = http.Headers(content_type="multipart/form-data")
-    assert not view(v, headers=h)
+    assert not view(v, content_type="multipart/form-data")
 
-    h = http.Headers(content_type="unparseable")
-    assert not view(v, headers=h)
+    assert not view(v, content_type="unparseable")
+
+
+def test_render_priority():
+    v = multipart.ViewMultipart()
+    assert v.render_priority(b"", content_type="multipart/form-data")
+    assert not v.render_priority(b"", content_type="text/plain")
diff --git a/test/mitmproxy/contentviews/test_protobuf.py b/test/mitmproxy/contentviews/test_protobuf.py
index f0a91fd15..2fabf19af 100644
--- a/test/mitmproxy/contentviews/test_protobuf.py
+++ b/test/mitmproxy/contentviews/test_protobuf.py
@@ -28,3 +28,10 @@ def test_format_pbuf(filename, tdata):
         expected = f.read()
 
     assert protobuf.format_pbuf(input) == expected
+
+
+def test_render_priority():
+    v = protobuf.ViewProtobuf()
+    assert v.render_priority(b"", content_type="application/x-protobuf")
+    assert v.render_priority(b"", content_type="application/x-protobuffer")
+    assert not v.render_priority(b"", content_type="text/plain")
diff --git a/test/mitmproxy/contentviews/test_query.py b/test/mitmproxy/contentviews/test_query.py
index 1ae1b3acb..606300bca 100644
--- a/test/mitmproxy/contentviews/test_query.py
+++ b/test/mitmproxy/contentviews/test_query.py
@@ -1,13 +1,23 @@
 from mitmproxy.contentviews import query
-from mitmproxy.coretypes import multidict
+from mitmproxy.test import tutils
 from . import full_eval
 
 
 def test_view_query():
     d = ""
     v = full_eval(query.ViewQuery())
-    f = v(d, query=multidict.MultiDict([("foo", "bar"), ("foo", "baz")]))
+    req = tutils.treq()
+    req.query = [("foo", "bar"), ("foo", "baz")]
+    f = v(d, http_message=req)
     assert f[0] == "Query"
     assert f[1] == [[("header", "foo: "), ("text", "bar")], [("header", "foo: "), ("text", "baz")]]
 
     assert v(d) == ("Query", [])
+
+
+def test_render_priority():
+    view = query.ViewQuery()
+    req = tutils.treq()
+    req.query = [("foo", "bar"), ("foo", "baz")]
+    assert view.render_priority(b"", http_message=req)
+    assert not view.render_priority(b"")
diff --git a/test/mitmproxy/contentviews/test_raw.py b/test/mitmproxy/contentviews/test_raw.py
index 0e6e1b340..d9fa44f89 100644
--- a/test/mitmproxy/contentviews/test_raw.py
+++ b/test/mitmproxy/contentviews/test_raw.py
@@ -5,3 +5,9 @@ from . import full_eval
 def test_view_raw():
     v = full_eval(raw.ViewRaw())
     assert v(b"foo")
+
+
+def test_render_priority():
+    v = raw.ViewRaw()
+    assert v.render_priority(b"anything")
+    assert not v.render_priority(b"")
diff --git a/test/mitmproxy/contentviews/test_urlencoded.py b/test/mitmproxy/contentviews/test_urlencoded.py
index d01f9aaae..6c25fdd51 100644
--- a/test/mitmproxy/contentviews/test_urlencoded.py
+++ b/test/mitmproxy/contentviews/test_urlencoded.py
@@ -13,3 +13,9 @@ def test_view_urlencoded():
     assert v(d)
 
     assert not v(b"\xFF\x00")
+
+
+def test_render_priority():
+    v = urlencoded.ViewURLEncoded()
+    assert v.render_priority(b"", content_type="application/x-www-form-urlencoded")
+    assert not v.render_priority(b"", content_type="text/plain")
diff --git a/test/mitmproxy/contentviews/test_wbxml.py b/test/mitmproxy/contentviews/test_wbxml.py
index 441a77497..1497f41c6 100644
--- a/test/mitmproxy/contentviews/test_wbxml.py
+++ b/test/mitmproxy/contentviews/test_wbxml.py
@@ -18,3 +18,10 @@ def test_wbxml(tdata):
 
     p = wbxml.ASCommandResponse.ASCommandResponse(input)
     assert p.xmlString == expected
+
+
+def test_render_priority():
+    v = wbxml.ViewWBXML()
+    assert v.render_priority(b"", content_type="application/vnd.wap.wbxml")
+    assert v.render_priority(b"", content_type="application/vnd.ms-sync.wbxml")
+    assert not v.render_priority(b"", content_type="text/plain")
diff --git a/test/mitmproxy/contentviews/test_xml_html.py b/test/mitmproxy/contentviews/test_xml_html.py
index 82f85c155..0f5c3983f 100644
--- a/test/mitmproxy/contentviews/test_xml_html.py
+++ b/test/mitmproxy/contentviews/test_xml_html.py
@@ -34,3 +34,12 @@ def test_format_xml(filename, tdata):
         expected = f.read()
     tokens = xml_html.tokenize(input)
     assert xml_html.format_xml(tokens) == expected
+
+
+def test_render_priority():
+    v = xml_html.ViewXmlHtml()
+    assert v.render_priority(b"", content_type="text/xml")
+    assert v.render_priority(b"", content_type="text/xml")
+    assert v.render_priority(b"", content_type="text/html")
+    assert not v.render_priority(b"", content_type="text/plain")
+    assert v.render_priority(b"<html/>")
diff --git a/test/mitmproxy/net/http/test_multipart.py b/test/mitmproxy/net/http/test_multipart.py
index 4a3f27933..860db09c8 100644
--- a/test/mitmproxy/net/http/test_multipart.py
+++ b/test/mitmproxy/net/http/test_multipart.py
@@ -1,13 +1,11 @@
+import pytest
+
 from mitmproxy.net.http import Headers
 from mitmproxy.net.http import multipart
-import pytest
 
 
 def test_decode():
     boundary = 'somefancyboundary'
-    headers = Headers(
-        content_type='multipart/form-data; boundary=' + boundary
-    )
     content = (
         "--{0}\n"
         "Content-Disposition: form-data; name=\"field1\"\n\n"
@@ -17,24 +15,17 @@ def test_decode():
         "value2\n"
         "--{0}--".format(boundary).encode()
     )
-
-    form = multipart.decode(headers, content)
+    form = multipart.decode(f'multipart/form-data; boundary={boundary}', content)
 
     assert len(form) == 2
     assert form[0] == (b"field1", b"value1")
     assert form[1] == (b"field2", b"value2")
 
     boundary = 'boundary茅莽'
-    headers = Headers(
-        content_type='multipart/form-data; boundary=' + boundary
-    )
-    result = multipart.decode(headers, content)
+    result = multipart.decode(f'multipart/form-data; boundary={boundary}', content)
     assert result == []
 
-    headers = Headers(
-        content_type=''
-    )
-    assert multipart.decode(headers, content) == []
+    assert multipart.decode("", content) == []
 
 
 def test_encode():
diff --git a/test/mitmproxy/proxy/test_events.py b/test/mitmproxy/proxy/test_events.py
index d6a791c6c..a860f746e 100644
--- a/test/mitmproxy/proxy/test_events.py
+++ b/test/mitmproxy/proxy/test_events.py
@@ -31,6 +31,6 @@ def test_command_completed():
     class FooCompleted1(events.CommandCompleted):
         command: FooCommand
 
-    with pytest.raises(RuntimeError, match="conflicting subclasses"):
+    with pytest.warns(RuntimeWarning, match="conflicting subclasses"):
         class FooCompleted2(events.CommandCompleted):
             command: FooCommand
diff --git a/test/mitmproxy/test_hooks.py b/test/mitmproxy/test_hooks.py
index ff934f539..a7288322f 100644
--- a/test/mitmproxy/test_hooks.py
+++ b/test/mitmproxy/test_hooks.py
@@ -24,7 +24,7 @@ def test_hook():
     assert e.args() == [b"foo"]
     assert FooHook in hooks.all_hooks.values()
 
-    with pytest.raises(RuntimeError, match="Two conflicting event classes"):
+    with pytest.warns(RuntimeWarning, match="Two conflicting event classes"):
         @dataclass
         class FooHook2(hooks.Hook):
             name = "foo"
diff --git a/test/mitmproxy/utils/test_strutils.py b/test/mitmproxy/utils/test_strutils.py
index 4759f1db4..3a928ff71 100644
--- a/test/mitmproxy/utils/test_strutils.py
+++ b/test/mitmproxy/utils/test_strutils.py
@@ -83,6 +83,7 @@ def test_is_mostly_bin():
 
 
 def test_is_xml():
+    assert not strutils.is_xml(b"")
     assert not strutils.is_xml(b"foo")
     assert strutils.is_xml(b"<foo")
     assert strutils.is_xml(b"  \n<foo")
diff --git a/tox.ini b/tox.ini
index db488980a..01fd1cc45 100644
--- a/tox.ini
+++ b/tox.ini
@@ -40,7 +40,7 @@ commands =
 passenv = CI_* GITHUB_* AWS_* TWINE_* DOCKER_*
 deps =
   -e .[dev]
-  pyinstaller==4.1
+  pyinstaller==4.2
   twine==3.3.0
   awscli
 commands =