WebProxy portlet does not work with a post form

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.0.X, Master
• Fix Version/s: 7.0.0 DXP FP44, 7.0.6 CE GA7, 7.0.0 DXP SP8, 7.0.X, 7.1.0 M2, 7.1.X, Master
• Component/s: Util > Web Proxy
• Labels:
  • QA-B
  • ee-ts
  • liferay-digital-enterprise-70-sp8
  • liferay-fixpack-de-44-7010
• Branch Version/s:
  7.0.x
• Backported to Branch:
  Committed
• Fix Priority: 4
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/55612

Reproduction Steps:

1. Set up Liferay 7.0 with de-32 and add the property: javascript.single.page.application.enabled=false to your portal-ext.properties file and start it.

2. Create a Site and add a Page to it.

3. Add a Web Proxy Portlet to the Page.

4. Click on 3 dots on the upper right of Portlet and select Configuration --> then add https://www.w3schools.com/php/demo_form_validation_complete.php to URL

5. Open URL in a separate page and submit the form.

6. In Portlet try to submit the form.

Actual Result: After long time of loading the form is not submitted and an exception is thrown (see attachment, webproxyerror.txt).

Expected Result: Form should be successfully submitted as when submitting it directly from the site.

 7.0.x @ 788161b414cefb00a136311c0fd55391a431eeee

 Master @ eabcdfb714fb62a98a4b348ab525af902363163a