#507

04.07.2011 19:51
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One problem when relaunching large projects with a ton of images is to re-create all the thumbnails that users have uploaded in the years. If you don’t use paperclip (ruby) or anything like it in PHP (is there any like it!?) where you can run run one command to re-create all the thumbnails in all specified sizes your can try to keep it flexible and create every image on demand.

Theory

The Webserver should serve the image if it exists. If the file does not exist, the request should be redirected to a PHP script that searches and creates the requested image file (in requested size) at exactly the location it was originally requested. The second request on the file will not be redirected to the PHP script and will server the image that now exists.

Practice

So the first thing to archive is to send the request of a not existing image to a PHP file. That’s easy if you’re familiar with all the nginx directives:

This rule can be combined with the anti-hotlinking rules for images with nginx I showed you last week.

After that we need to create a format that includes width and height of any requested image so that the

thumbnailer.php

knows which size the created image should have. A valid request for a resized file should always have all parameters (width, height) in it:

../img/public/9c4be029/438xauto/filename.jpg

This makes it easy to split up width, height with a regexp in

thumbnailer.php

. The following code is just an example. You’re surelly integrate the logic into your frameworks:

That’s it! After that you can request any image in any size on your webserver by only creating it once it’s requested.

There are some things you can add, like other parameters in the

$formatRegexp

string to add different resizing methods or even filters, or limitations on the

width

and

height

parameter.

Appendix: Apache

It’s almost the same thing with apache. Just add a few lines to your

.htaccess.

and all your image requests are redirected to the thumbnailer (or anything):

#457

05.06.2009 13:49
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iTerm ist eine willkommene Alternative zu der nativen Terminal App für OSX. Jetzt kann man die auch mit AppleScript verwursten.
Wenn man es Leid ist immer wieder die selben Terminal Fenster aufzumachen um Apache-Logs zu lesen oder die Datenbank zu überwachen sollte man überlegen ob das nicht noch besser geht. Klaro geht das besser! Mit Apple-Script!


tell application "iTerm"

  activate

  

  -- create server log terminal

  make new terminal

  tell the last terminal

    activate current session

    launch session "Default Session"

    tell the last session

      write text "clear;"

      write text "tail -f /Applications/MAMP/logs/apache_access.log"

      set background color to {15000, 200, 200}

    end tell

  end tell

  set the bounds of the first window to {0, 700, 840, 900}

  set the name of the first window to "apace_access.log"

  

  -- creat working terminal

  make new terminal

  tell the last terminal

    activate current session

    launch session "Default Session"

    tell the last session

      write text "welcome user, start now"

    end tell

  end tell

  set the bounds of the first window to {0, 0, 840, 660}

  set the name of the first window to "workspace"

  

end tell

So kann man ganze Fenster Setups zusammencoden und erspart sich so hoffentlich einen Haufen Zeit.

Nachtrag:
Man kann dann das Apple-Script auch automatisch bei jedem Start von iTerm ausführen lassen indem man es in ~/Library/iTerm/AutoLaunch.scpt ablegt. Weitere Beispiele gibt es auf der Scripting Seite von iTerm.

#456

04.06.2009 10:07
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Viele von den PHP Codern da draussen kennen es wahrscheinlich schon, aber ich will trotzdem mal darauf hinweisen. Datei Uploads in PHP sind ja manchmal etwas verwirrend, vor allem was verschiedene Fehlerquellen angeht. Um schon im Vorhinein Fehler abzufangen bietet sich folgendes Code-Snippet an:


// test if a file was uploaded

$formFieldName = 'myFile';

if (isset($_FILES[$formFieldName])) {

  switch(@$_FILES[$formFieldName]['error']) {

    case UPLOAD_ERR_OK: // 0

      // everything is ok with the upload for php

      break;

    case UPLOAD_ERR_INI_SIZE:

      // file is larger than the size set in php.ini

      // upload_max_filesize

      break;

    case UPLOAD_ERR_FORM_SIZE:

      // file exceeds size set in form

      break;

    case UPLOAD_ERR_PARTIAL:

      // file upload 

      break;

    case UPLOAD_ERR_NO_FILE:

      // no file was specified (empty form field)

      break;

    case UPLOAD_ERR_NO_TMP_DIR:

      // no tmp dir specified in php.ini

      break;

    case UPLOAD_ERR_CANT_WRITE:

      // tmp dir from php.ini is not writable for php

      break;

    default:

      // unknown error code

      break;

  }

}

Wie man sieht bietet PHP weit aus mehr Möglichkeiten fehlgeschlagene Datei-Uploads zu erkennen als manchen bewusst ist. Vor allem wenn große Dateien hochgeladen werden die zu groß sind (upload_max_filesize) gibt PHP direkt einen Fehler aus, ohne riesen Dateien anzunehmen.