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curl, Bash and Firefox mutualism

As my career directs me to an API First way of working I start to looking for ways to improve my development processes related to HTTP requests.

One really nice work flow for debugging services is through CURL+Bash+Firefox ‘mutualism’. I’ll describe the precess I usually take below.

The Request

When I need to test a request there’s two common cases. First, I never used the request before so I have to write one from stratch with CURL. When the service is already being used I can simply get a copy of the CURL request made by the browser.

Any way, I usually end up with a request like this.

curl -X POST -H "Authorization: token" \
-H "Content-Type: application/x-www-form-urlencoded" \
http://clipp.dev/report/v1/finance.get_revenue.html  -d "filters[]"

Automating the parts

The next step I take is to update dynamic parts of the request through scripts.

curl -X POST -H "Authorization: $(clipp-get-token)" \
-H "Content-Type: application/x-www-form-urlencoded" \
http://clipp.dev/report/v1/finance.get_revenue.html  -d "filters[]"

In this case I created a Bash script called clipp-get-token, it’s purpose is to return me a properly formatted and valid authentication token so I don’t have to bother with token timeouts.

The relevant part of the script is as it follows.

result=`curl -X POST -H "Content-Type: application/x-www-form-urlencoded" \
-d "login=$user&password=$passwd" http://clipp.dev/rpc/v1/application.authenticate.json`
result=`echo $result | cut -d':' -f3 | cut -d'"' -f2`
echo "$result"

The Result

The final step of the “mutualism” is, when appropriate, to redirect back to Firefox the request result so the browser is able to render it properly. There are many hard ways of doing that, like saving the CURL output on a file and opening it with Firefox. Hopefully I found out a way to send the CURL output to Firefox as a stream of text instead of a file.

To achieve that, you must use firefox as it follows:

echo "stream" | firefox-developer "data:text/html;base64,$(base64 -w 0 <&0)"

Note: It only works with pipe, I’m yet to find a way to achieve the same with a redirection <<.

This is specially useful when the server returns HTML because inspecting it on the terminal it’s not so good. But works as well with XML, even JSON is returned in a nice visual way. To illustrate a complete example of the flow is the request below.

curl -X POST -H "Authorization: $(clipp-get-token)" \
-H "Content-Type: application/x-www-form-urlencoded" \
http://clipp.dev/report/v1/finance.get_revenue.html  -d "filters[]" | sfox

Sfox for stream firefox is simply a alias for the string previously showed, this way is clear and concise.

alias sfox='firefox-developer "data:text/html;base64,$(base64 -w 0 <&0)"'


I like CURL on the terminal mainly because it’s more reliable for testing than on the application itself. The application is more propense to frontend bugs.

Another good point of CURL is that it’s pure plain text so making scripts on Bash to it is extremly easy.

Going further on my mutualism analogy, I could make an script to remove Firefox “crap headers” from the request. Another good point of research is to use the output as a parameter on an URL to be consumed and viewed through Firefox.

Is up to the developer creativity to use old tools with new purposes and achieve new heights.

Critics, advices and comments are appreciated.