Solution for sub_filter issue in Nginx

Examination of sub_filter issue in Nginx

Sometimes during the initialization and performance of the Nginx server, you may encounter an issue where sub_filter does not properly process the returned JSON responses. This situation is usually due to incorrect server configurations or when gzip is enabled.

In such cases, the first step is to check the gzip settings in the Nginx configuration file. Ensuring that this feature is properly configured can help resolve the issue. gzip automatically compresses response files like JSON to reduce size and increase the speed of returned responses.

Proposed Solution

In most cases, disabling the gzip compression or ensuring correct bundling and applying gzip to the content can address the sub_filter issue. However, if you are in a situation where you are unable to disable gzip, you should not turn it off completely as it can lead to significant performance drawbacks.

Carefully reviewing the Nginx configuration file for directives related to gzip and sub_filter is essential. These directives define the primary settings for applying filters and compression to the specified output.

Examples of Configuration

Here is an example code snippet demonstrating how to configure via the sub_filter to resolve the issue:

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_pass http://backend_server;
        gzip off;
        sub_filter 'http://backend_server' 'https://example.com';
        sub_filter_once off;
    }
}

Code Explanation