Nginx processes HTTP requests in multiple phases. In each of the phases there might be 0 or more handlers called. In the Nginx source code phases have specific constants associated with them. Here is a list of all phases:

1. NGX_HTTP_SERVER_REWRITE_PHASE — the phase of request URI transformation on virtual server level;
2. NGX_HTTP_FIND_CONFIG_PHASE — the phase of configuration location lookup;
3. NGX_HTTP_REWRITE_PHASE — the phase of request URI transformation on location level;
4. NGX_HTTP_POST_REWRITE_PHASE — request URI transformation post-processing phase;
5. NGX_HTTP_PREACCESS_PHASE — access restrictions check preprocessing phase;
6. NGX_HTTP_ACCESS_PHASE — access restrictions check phase;
7. NGX_HTTP_POST_ACCESS_PHASE — access restrictions check post-processing phase;
8. NGX_HTTP_TRY_FILES_PHASE — try_files directive processing phase;
9. NGX_HTTP_CONTENT_PHASE — content generation phase;
10. NGX_HTTP_LOG_PHASE — logging phase.

On every phase you can register any number of your handlers. Continue reading “HTTP request processing phases in Nginx” →