1391769 - Cannot POST a HTML <form> from moz-extension:// (WebExtensions)

Status: RESOLVED DUPLICATE of bug 1344465

(WebExtensions :: Untriaged, defect)

Description

[miika9764]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:55.0) Gecko/20100101 Firefox/55.0
Build ID: 20170811100700

Steps to reproduce:

- Start Firefox Nightly built from https://hg.mozilla.org/mozilla-central/rev/a6a1f5c1d971dbee67ba6eec7ead7902351ddca2
- Open about:debugging#addons
- Load the extension built from https://github.com/siikamiika/Image-Reverse-Search-WebExtension/commit/8769a8eccef2152f0be5a2edf6074271f6ef4b64 (this is a fork trying to add POST requests to reverse image search engines but currently only sends a hello world request to httpbin.org/post; relevant code in the commit behind the link)
- Right-click any image and select "Image Reverse Search"

(Can also be reproduced by manually POSTing any <form> from a page behind moz-extension://.)


Actual results:

Nightly navigates to http://httpbin.org/post (GET /post) and you see "405 Method Not Allowed".


Expected results:

A POST request with "hello=world&lorem=ipsum" should be sent to http://httpbin.org/post and you should see something like this: (the addon works on Chromium)

{
  "args": {}, 
  "data": "", 
  "files": {}, 
  "form": {
    "hello": "world", 
    "lorem": "ipsum"
  }, 
  "headers": {
    "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8", 
    "Accept-Encoding": "gzip, deflate", 
    "Accept-Language": "en-US,en;q=0.8,fi;q=0.6", 
    "Cache-Control": "max-age=0", 
    "Connection": "close", 
    "Content-Length": "23", 
    "Content-Type": "application/x-www-form-urlencoded", 
    "Host": "httpbin.org", 
    "Origin": "null", 
    "Upgrade-Insecure-Requests": "1", 
    "User-Agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36"
  }, 
  "json": null, 
  "origin": "*.*.*.*", 
  "url": "http://httpbin.org/post"
}