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 Old-School dkLab | Constructor | HTTP_ImageResizer: Load and resize images from non-file sources with nginx caching 

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This library misses a detailed documentation, but it is used in various production projects for a long time, so you may use it too. Below is the content of README.txt file.

HTTP_ImageResizer: Load and resize images from non-file sources with nginx caching.
(C) Dmitry Koterov,

This library is used to load static image content from anywhere (e.g. from a 
database, from remote storage etc.), resize it and return to browser. Fetching
and resizing is performed "on demand": images are resized when a request
arrives, but resized result is stored to nginx (or similar) cache, so there 
is no performance bottleneck.

1. Build an image URL

$signer = new HTTP_UrlSigner("very-secret-word",'*'); $resizer = new HTTP_ImageResizer($signer, null); $paramsToPassToProcessor = array( "w" => 20, "h" => 30, "format" => "jpeg", "bg" => "00FF00", "quality" => 90, // Everything else are custom parameters: "id" => 10, "any" => "other", ); echo '<img src="' . $resizer->getUrl($paramsToPassToProcessor) . '"/>'; Result looks like: <img src="" /> Passed parameters is encoded, signed and accessible in image.php processor.

2. Process an image request at image.php

<?php ... $signer = new HTTP_UrlSigner("very-secret-word",'*'); $resizer = new HTTP_ImageResizer($signer, "callbackImageRawContent"); $resizer->main($_SERVER['REQUEST_URI']); ... function callbackImageRawContent($paramsPassedToProcessor) { // $paramsPassedToProcessor["id"] and $paramsPassedToProcessor["other"] // are accessible here. return DB::selectCell( "SELECT raw FROM image WHERE id=?", $paramsPassedToProcessor['id'] ); // ...or similar }

3. Configure nginx caching (very important!)

fastcgi_cache_path /var/cache/nginx levels= keys_zone=cache:10m; ... location /image.php { fastcgi_cache cache; fastcgi_cache_valid 200 304 404 240h; fastcgi_cache_key "method=$request_method|ims=$http_if_modified_since|inm=$http_if_none_match|host=$host|uri=$request_uri"; fastcgi_hide_header "Set-Cookie"; fastcgi_ignore_headers "Cache-Control" "Expires"; ... # or use proxy_* commands if you use Apache, not FastCGI PHP } If you do not configure nginx (or similar) caching, resize process will be executed on each request, it is VERY slow! So be sure to use ab -n 10000 -c 10 after configuring nginx to test that caching works correctly.

Dmitry Koterov, Dk lab. ©1999-2020
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