Last week we experienced a little outage on our websites (We have a website with a lot of dependencies with external systems and third-party content). It gave us the opportunity to take a closer look at our products while having a production issue. One thing we noticed is that we don’t tell the end-user that we are having issues. We have learned that we have to built-in a more resilient user experience during issues.
We can simulate these kinds of failures while testing over a proxy. BrowserMob Proxy can be controlled by a REST interface and has some great capabilities, such as blacklisting and whitelisting certain URL patterns, simulating various bandwidth and latency and controlling DNS and request timeouts.
As I said, BrowserMob Proxy is a REST tool. In order to perform REST calls we have to install cURL.
Windows
- Download cURL from http://curl.haxx.se/
- Extract the compressed file
- Put curl.exe in c:/Windows/ (to enable curl from the command prompt)
Linux
- sudo apt-get install curl
Or some other installation command which is related to the Linux distribution.
Starting the proxy
- Download the source from http://bmp.lightbody.net/
- Extract the compressed file
- Open two command prompts
In the first command prompt
- navigate to the bin directory
- Start the proxy by entering
browsermob-proxy.bat -port 9090
the Linux equivalent
./browsermob-proxy -port 9090
In the second command prompt
- Perform the following curl command to create a new proxy,
curl -X POST http://localhost:9090/proxy
- This will return a new proxy port, something like: {“port”:9091}
- You can create a new HAR to start recording data, like this:
curl -X PUT -d ''initialPageRef=newHar'' http://localhost:9090/proxy/9091/har
Set the proxy in browser
- Navigate to Control Panel -> Internet Options * Goto LAN settings in the Connections tab
- Thick Use a proxy server for you LAN
- Fill in the address: localhost
- Fill in the port: 9091 (the one returned from the curl command)
- Click on OK twice
Limit the connection speed
Perform the following curl command in the command prompt:
curl -X PUT -d "downstreamKbps=50" http://localhost:9090/proxy/9091/limit
Now you can visit the website with a low connection speed.
Blacklist third-party content
Perform the following curl command in the command prompt:
curl -X PUT -d "regex=http://example.com/*.*&status=404" http://localhost:9090/proxy/9091/blacklist
Now you can visit the website while blacklisting some content.
Reference
Check the BrowserMob Proxy readme (on Github) for all available API commands.
