added external header server

changedetectionio/fetch_site_status.py

@@ -4,7 +4,8 @@ import os
 import re
 import time
 import urllib3
-
+import requests
+import simplejson
 from changedetectionio import content_fetcher, html_tools
 
 urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
@@ -67,6 +68,18 @@ class perform_site_check():
 
         # Tweak the base config with the per-watch ones
         request_headers = self.datastore.data['settings']['headers'].copy()
+
+        if self.datastore.get_val(uuid, 'external_header_server') is not None:
+            try:
+                resp = requests.get(self.datastore.get_val(uuid, 'external_header_server'))
+                if resp.status_code != 200:
+                    raise Exception("External header server returned non-200 response. Please check the URL for the server")
+            
+                request_headers.update(resp.json())
+
+            except simplejson.errors.JSONDecodeError:
+                raise Exception("Failed to decode JSON response from external header server")
+                
         request_headers.update(extra_headers)
 
         # https://github.com/psf/requests/issues/4525

changedetectionio/forms.py

@@ -336,6 +336,7 @@ class watchForm(commonSettingsForm):
     title = StringField('Title', default='')
 
     ignore_text = StringListField('Ignore text', [ValidateListRegex()])
+    external_header_server = fields.URLField('External Header Server', validators=[validateURL()])
     headers = StringDictKeyValue('Request headers')
     body = TextAreaField('Request body', [validators.Optional()])
     method = SelectField('Request method', choices=valid_method, default=default_method)

changedetectionio/model/Watch.py

@@ -25,6 +25,7 @@ class model(dict):
             'previous_md5': False,
             'uuid': str(uuid_builder.uuid4()),
             'headers': {},  # Extra headers to send
+            'external_header_server': None,  # URL to a server that will return headers
             'body': None,
             'method': 'GET',
             #'history': {},  # Dict of timestamp and output stripped filename

changedetectionio/templates/edit.html

@@ -109,6 +109,12 @@
                     <div class="pure-control-group" id="request-method">
                         {{ render_field(form.method) }}
                     </div>
+                    <div class="pure-control-group" id="external-header-server">
+                        {{ render_field(form.external_header_server, placeholder="http://example.com/watch1") }}
+                        <div class="pure-form-message-inline">
+                            The watch will perform a GET request before each check to this URL and will use the headers in addition to the ones listed below and in global settings. <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Run-JavaScript-before-change-detection">More help and examples here</a>
+                        </div>
+                    </div>
                     <div class="pure-control-group" id="request-headers">
 {{ render_field(form.headers, rows=5, placeholder="Example
 Cookie: foobar