Sleipnir is a very little proxy which can serve some local files instead of the requested ones.

First, copy the config.csv.dist file to config.csv.

Then, edit the csv. This is the pattern of each row :

<url to catch>,<content type of the response>,<location of the file to server instead>

The <url to catch> must be a valid regexp.

By example you can create the following config file :

path,contentType,file
.*.png,image/jpeg,myLolCat.jpg

which replace all png images by a nice jpeg cat.

Run it :

go build sleipnir.go
./sleipnir

or download a binary if exists.

Usage :

./sleipnir -h
Usage of ./sleipnir:
  -a=":8888": Bind to this address:port
  -c="config.csv": Config file
  -h=false: Print this help
  -v=false: Verbose

See the beautiful example in the download section!