Troubleshooting GitLab Web IDE Error When Trying to Edit a File on a Private GitLab Using Apache Reverse Proxy

GitLab Web IDE is a powerful web-based integrated development environment that allows users to edit, commit, and manage their GitLab projects directly from the browser. However, some users may encounter an error while trying to edit files in the Web IDE when accessing GitLab through an Apache reverse proxy. This article provides a step-by-step solution to resolve the “Error while loading the project data. Please try again” message that appears in this scenario.

Problem Description

When attempting to use the GitLab Web IDE on a private GitLab instance accessed through an Apache reverse proxy, users encounter the error message “Error while loading the project data. Please try again.”

Solution

To resolve this issue, you need to configure the Apache reverse proxy to properly handle WebSocket connections for the GitLab Web IDE. Follow the steps below to set up the Apache reverse proxy for WebSocket:

Step 1: Edit Apache Configuration

Open the Apache configuration file on your server. Depending on your distribution, the file may be located in different directories such as /etc/apache2/apache2.conf or /etc/httpd/httpd.conf. You may also have separate configuration files in the /etc/apache2/sites-available/ or /etc/httpd/conf.d/ directory.

Step 2: Enable ‘AllowEncodedSlashes’ Directive

Locate the <VirtualHost> block for your GitLab instance in the Apache configuration file. Inside the block, add or modify the AllowEncodedSlashes directive and set it to NoDecode. This step is essential for handling GitLab URLs correctly.

Example

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<VirtualHost *:80>
    ServerName gitlab.example.com
    ...
    AllowEncodedSlashes NoDecode
    ...
</VirtualHost>

Step 3: Enable WebSocket Proxy

Within the same <VirtualHost> block, enable the WebSocket proxy by adding the following Rewrite rules. These rules will redirect WebSocket requests to the GitLab server:

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<VirtualHost *:80>
    ServerName gitlab.example.com
    ...
    AllowEncodedSlashes NoDecode

    RewriteEngine On

    # Handle WebSocket upgrade requests
    RewriteCond %{HTTP:Upgrade} =websocket [NC]
    RewriteRule /(.*) ws://localhost:30080/$1 [P,QSA,NE]

    # Handle other HTTP requests
    RewriteCond %{HTTP:Upgrade} !=websocket [NC]
    RewriteRule /(.*) http://localhost:30080/$1 [P,QSA,NE]
    ...
</VirtualHost>

Make sure to replace gitlab.example.com with the domain or IP address used to access your GitLab instance. The WebSocket connections will be redirected to the GitLab server on port 30080.

Step 4: Restart Apache

After making the changes, save the Apache configuration file and restart Apache to apply the modifications:

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# For Ubuntu/Debian
sudo service apache2 restart

# For CentOS/RHEL
sudo systemctl restart httpd

Conclusion

By following the steps outlined in this article, you should be able to resolve the “Error while loading the project data. Please try again” message encountered when using the GitLab Web IDE on a private GitLab instance accessed through an Apache reverse proxy. The setup allows WebSocket connections to be correctly handled, ensuring a smooth and error-free experience with the Web IDE.

Remember to always make backups of your configuration files before making changes and verify your setup’s correctness to avoid potential issues.