Add a custom-headers setting

Supersedes #1132
Closes #1020.

CHANGELOG.asciidoc

@@ -21,6 +21,7 @@ Added
 ~~~~~
 
 - New `:edit-url` command to edit the URL in an external editor.
+- New `network -> custom-headers` setting to send custom headers with every request.
 
 Changed
 ~~~~~~~

qutebrowser/browser/network/networkmanager.py

@@ -398,6 +398,13 @@ class NetworkManager(QNetworkAccessManager):
         req.setRawHeader('DNT'.encode('ascii'), dnt)
         req.setRawHeader('X-Do-Not-Track'.encode('ascii'), dnt)
 
+        # Load custom headers
+        custom_headers = config.get('network', 'custom-headers')
+
+        if custom_headers is not None:
+            for header, value in custom_headers.items():
+                req.setRawHeader(header.encode('ascii'), value.encode('ascii'))
+
         # There are some scenarios where we can't figure out current_url:
         # - There's a generic NetworkManager, e.g. for downloads
         # - The download was in a tab which is now closed.

qutebrowser/config/configdata.py

@@ -401,6 +401,10 @@ def data(readonly=False):
              SettingValue(typ.Bool(), 'true'),
              "Whether to try to pre-fetch DNS entries to speed up browsing."),
 
+            ('custom-headers',
+             SettingValue(typ.HeaderDict(none_ok=True), ''),
+             "Set custom headers for qutebrowser HTTP requests."),
+
             readonly=readonly
         )),
 

tests/integration/features/misc.feature

@@ -362,3 +362,10 @@ Feature: Various utility commands.
         And I press the key "<Tab>"
         And I press the key "<Ctrl-C>"
         Then no crash should happen
+
+    ## Custom headers
+
+    Scenario: Setting a custom header
+        When I set network -> custom-headers to {"X-Qute-Test": "testvalue"}
+        And I open headers
+        Then the header X-Qute-Test should be set to testvalue