How to run BrowserMob Proxy with RobotFramework and Capture HAR files - robotframework

Question

I have written this code in robotframework
${proxy}= | Evaluate | sys.modules['selenium.webdriver'].Proxy() sys, selenium.webdriver |
${proxy.http_proxy}= | Set Variable | 127.0.0.1:8080 |
Create Webdriver | Firefox proxy=${proxy} |
Go To | http://www.knowledgefarm.in/tst/a.html |
And I am running BrowserMob proxy from command line like this:
browsermob-proxy.bat --address 127.0.0.1 --port 8080
Now, when i run robotframework, it open the browser and simple give this message on page.
HTTP ERROR: 404
Problem accessing /tst/a.html. Reason:
Not Found
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Two questions:
why my pages are not loaded. (it works if I remove proxy setting)
After the workaround, how do I specify to generate HAR file and how should I specify the location of HAR file

Answer 1

The above code does not actually start a proxy. To start a proxy, you need to run these commands.
Create | http context | localhost:8080 | http
Post | /proxy
${json} | Get Response Body
${port} | Get Json Value | ${json} | /port
${proxy}= | Evaluate | sys.modules['selenium.webdriver'].Proxy() | sys,selenium.webdriver
${proxy.http_proxy}= | Set Variable | 127.0.0.1:${port}
Create Webdriver | Firefox | proxy=${proxy}
Go To | ${LOGIN URL}
Set Request Body | pageRef=LOGIN&captureContent=false&captureHeaders=true
PUT | /proxy/${port}/har
${json} | HttpLibrary.HTTP.Get Response Body
OperatingSystem.Create File | D:\\myfile.har | ${json}