Add httpdump.py example (#5190)

* add httpdump.py example

* update CHANGELOG.md

* delete print() statement

* fix flake8?

CHANGELOG.md

@@ -2,7 +2,8 @@
 
 ## Unreleased: mitmproxy next
 
-* Add flatpak support to the browser addon (@pauloromeira)
+* Add flatpak support to the browser addon (#5200, @pauloromeira)
+* Add example addon to dump contents to files based on a filter expression (#5190, @redraw)
 
 ## 19 March 2022: mitmproxy 8.0.0
 

examples/contrib/httpdump.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python
+# dump content to files based on a filter
+# usage: mitmdump -s httpdump.py "~ts application/json"
+#
+# options:
+#   - dumper_folder: content dump destination folder (default: ./httpdump)
+#   - open_browser: open integrated browser with proxy configured at start (default: true)
+#
+# remember to add your own mitmproxy authorative certs in your browser/os!
+# certs docs: https://docs.mitmproxy.org/stable/concepts-certificates/
+# filter expressions docs: https://docs.mitmproxy.org/stable/concepts-filters/
+import os
+import mimetypes
+from pathlib import Path
+
+from mitmproxy import flowfilter
+from mitmproxy import ctx, http
+
+
+class HTTPDump:
+    def load(self, loader):
+        self.filter = ctx.options.dumper_filter
+
+        loader.add_option(
+            name = "dumper_folder",
+            typespec = str,
+            default = "httpdump",
+            help = "content dump destination folder",
+        )
+        loader.add_option(
+            name = "open_browser",
+            typespec = bool,
+            default = True,
+            help = "open integrated browser at start"
+        )
+
+    def running(self):
+        if ctx.options.open_browser:
+            ctx.master.commands.call("browser.start")
+
+    def configure(self, updated):
+        if "dumper_filter" in updated:
+            self.filter = ctx.options.dumper_filter
+
+    def response(self, flow: http.HTTPFlow) -> None:
+        if flowfilter.match(self.filter, flow):
+            self.dump(flow)
+
+    def dump(self, flow: http.HTTPFlow):
+        if not flow.response:
+            return
+
+        # create dir
+        folder = Path(ctx.options.dumper_folder) / flow.request.host
+        if not folder.exists():
+            os.makedirs(folder)
+
+        # calculate path
+        path = "-".join(flow.request.path_components)
+        filename = "-".join([path, flow.id])
+        content_type = flow.response.headers.get("content-type", "").split(";")[0]
+        ext = mimetypes.guess_extension(content_type) or ""
+        filepath = folder / f"{filename}{ext}"
+
+        # dump to file
+        if flow.response.content:
+            with open(filepath, "wb") as f:
+                f.write(flow.response.content)
+            ctx.log.info(f"Saved! {filepath}")
+
+
+addons = [HTTPDump()]