Critter provides two services: proxy service and a traffic control service.

• The proxy service is a pass-through server that usually sits between a http client and a http server.

• The traffic control service is used to change the behavior of the proxy service with respect to request and response handling. Information about what to do with a request or a response is available through a traffic manager.

Critter uses rules (xml) to specify what should happen to a request that it receives or response that it returns. For each incoming http request, the proxy service will ask the traffic manager for a rule that matches that request.

• A rule matches if all its conditions are met. A rule can use conditions that look at the host, port, path, header or a combination thereof. If such a rule is found then all its actions are performed.

• A rule can have actions that change the request, headers, body or those of the response. All its actions are performed in the order as listed in the rule.

• A rule has a name and can be disabled. Rules are defined in XML. Rules are managed (crud) using the REST interface of the traffic service.

The proxy service itself can be terminated and started using the traffic service.

Check out the sources

git clone https://github.com/emicklei/critter.git

Build using Maven

mvn clean install                           

Installation archive is now available

./target/critter-<version>-pkg.zip

Unzip the archive

./bin
./lib
./conf	  

Modify the configuration

./conf/critter.properties

Default content is

# proxy.host is the binding address for the http listen sockets
proxy.host=localhost
proxy.port=8888

# access to the traffic manager (GUI and REST)
traffic.port=8877

# If this property is set then rules are persistent in MongoDB 
#rule.database.mongo.host=localhost
#rule.database.mongo.port=27017

# If this property is enabled, an embedded H2 database is used. 
# The database file is stored in the critter/bin folder.
rule.database.h2.enabled=true      

sh ./bin/start.sh

Build a new image

mvn clean package docker:build

And run it (see pom.xml for the exact version)

docker run --name critter -P critter/critter:1.4.4

Use docker ps to find out to which host ports critter has been bound

If you require to connect to the outside world through a proxy, there are multiple options:

• Define the forward proxy in the critter.properties:

  forward proxy is the proxy that is used to make the outgoing connection.

  forward.http.proxy=http://192.168.128.1:1234 forward.https.proxy=http://192.168.128.1:1234 forward.no.proxy=www.google.nl,www.yahoo.com

• Use standard environment variables:

  https_proxy=http://192.168.128.1:1234 http_proxy=http://192.168.128.1:1234
  no_proxy=www.google.nl,www.yahoo.com
  h2=false

• Use non-standard environment variables (where standard environmental variables cannot be used):

  forwardHttpsProxy=http://192.168.128.1:1234 forwardHttpProxy=http://192.168.128.1:1234 forwardNoProxy=www.google.nl,www.yahoo.com

http://localhost:8877

2013 - 2016 (c) ernestmicklei.com, Apache 2 License