Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
From: Arno Welzel <usenet@arnowelzel.de>
Newsgroups: comp.lang.javascript
Subject: Re: missing image error
Date: Wed, 5 Aug 2020 07:49:00 +0200
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James Kirk:

> In Message: <hoskjfFefplU1@mid.individual.net>
> Arno Welzel <usenet@arnowelzel.de> wrote:
[...]
>> The only way to avoid 404 errors would be a wrapper script on the
>> *server* which will either return the actual image or a placeholder
>> if the image can not be loaded:
> 
>> <img src="server-side-loader?image=myimage.jpg" ...>
> 
>> Where "server-side-loader" is a PHP script etc. which will try to
>> load the specificed image file and if this is not possible return
>> the placeholder.
> 
> 𝐬𝐞𝐫v𝐞𝐫 𝐜𝐨𝐧𝐟𝐢𝐠𝐮𝐫𝐚𝐭𝐢𝐨𝐧 
> 
>    RewriteCond %{REQUEST_FILENAME} !-f 
>    RewriteCond %{REQUEST_URI} /img/.*\.(jpg|png|svg)$ [NC]
>    RewriteRule . /img/funnyClown.jpg [L]
> 
> If the server generates a listing.

Yep - this is a more elegant solution if you use Apache. And this should
also work without directory index enabled.

Also see: <https://httpd.apache.org/docs/2.4/rewrite/>

But in addition you also need this:

RewriteEngine on

And just to be sure: the Apache rewrite module must also be enabled on
the server.

The above rules translate as following:

1) RewriteCond %{REQUEST_FILENAME} !-f

If the requested resource is not an existing file

2) RewriteCond %{REQUEST_URI} /img/.*\.(jpg|png|svg)$ [NC]

If the requested URI starts with "/img/" and ends with ".jpg", ".png" or
".svg". The flags [NC] are for "no case", so the path or extension can
also be ".JPG" or the path may start with "/IMG/" as well.

3) RewriteRule . /img/funnyClown.jpg [L]

Response with a temporary redirect (HTTP 302) to /img/funnyClown.jpg and
stop evalulation any other rule following ([L]).


-- 
Arno Welzel
https://arnowelzel.de