This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
Ah, C. The best lingua franca we have… because we have no other lingua francas. Linguae franca. Surgeons general? C is fairly old — 44 years, now! — and comes from a time when there were possibly more architectures than programming languages. It works well for what it is, and what it is is a relatively simple layer of indirection atop assembly. Alas, the popularity of C has led to a number of programming languages’ taking significant cues from its design, and parts of its design are… slightly questionable. I’ve gone through some common features that probably should’ve stayed in C and my justification for saying so. The features are listed in rough order from (I hope) least to most controversial. The idea is that C fans will give up when I call it “weakly typed” and not even get to the part where I rag on braces. Wait, crap, I gave it away.
I hope I’m not alone on this but I find the cURL documentation hard to follow and short on examples.
My goal was to mimic some HTTP XML posting traffic a server gets from IoT devices. Google Chrome Postman (or Postman REST Client) reproduction is very easy and will send.
TL;DR
ensure you have an empty --header "Content-Type:" header: this ensures that cURL doesn’t add one and does not mess on how the content is being transferred.
use the --data or --data-binary command with an @ to post a file as body.
if you want --write-out then be sure you have a recent cURL version.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
This will hang the connection: somehow cURL will never notify the upload is done and the HTTP server keeps waiting. When you put --verbose or --trace-ascii - on the command-line you will see something like this before hanging: * upload completely sent off: 245 out of 245 bytes.
This will automatically add a Content-Length: 245 header and complete the transfer. But it will also add a Content-Type: application/x-www-form-urlencoded header causing the content not being posted as a body.
This will automatically ad a Content-Length: xxx header (way longer than 245) because it converts the request into a Content-Type: multipart/form-data; boundary=------------------------e1c0d47bac806954 one (the hex at the end differs) which is totally unlike what Postman does.
It is also unlike to what the HTTP server accepts.
It turns out that --data-ascii is exactly the same as --data and that --data-binary just skips some new-line conversion when compared to --data or --data-ascii. Contrary to the --data-raw documentation that suggest it is equivalent to --data-binary it seems --data-raw behaves exactly like --data and --data-ascii. Odd.
So these are all stuck with the Content-Type: application/x-www-form-urlencoded and I thought I was running out of options.
It posts exactly the same content as the IoT devices and Postman do.
Phew!
I tried to combine this with the --write-out (a.k.a. -w) option, but for older versions of cURL (I could reproduce with 7.34) that forces cURL back in to Content-Type: application/x-www-form-urlencoded mode so watch your cURL version!
Later I will put more research in chuncked transfer. Links that might help me:
#creates a new file descriptor 3 that redirects to 1 (STDOUT)
exec 3>&1
# Run curl in a separate command, capturing output of -w "%{http_code}" into HTTP_STATUS
# and sending the content to this command's STDOUT with -o >(cat >&3)
HTTP_STATUS=$(curl -w "%{http_code}" -o >(cat >&3) 'http://example.com')
Sort of tanslated from the first “via” (note that “mit Alles und Scharf” is hard to translate; it’s somewhere between “everything but the kitchen sink, but done right” and “right on the money”):
Bash Prompt Overkill: https://github.com/nojhan/liquidprompt is a Bash “Prompt doing it all right”-extension, which doesn’t care how much any feature costs as we have cores, gigabytes and SSD.
Liquid Prompt automagically recognises context and enables a plethora of features in the prompt when needed based on that context.
It’s like pixie dust for your prompt.
You can configure everything, but you don’t have to: the out of the box experience is already like pixie dust for your prompt.
It works on OS X too and is part of homebrew:
$ brew install liquidprompt
==> Using the sandbox
==> Downloading https://github.com/nojhan/liquidprompt/archive/v_1.11.tar.gz
==> Downloading from https://codeload.github.com/nojhan/liquidprompt/tar.gz/v_1.11
######################################################################## 100.0%
==> Caveats
Add the following lines to your bash or zsh config (e.g. ~/.bash_profile):
if [ -f /usr/local/share/liquidprompt ]; then
. /usr/local/share/liquidprompt
fi
If you'd like to reconfigure options, you may do so in ~/.liquidpromptrc.
A sample file you may copy and modify has been installed to
/usr/local/share/liquidpromptrc-dist
Don't modify the PROMPT_COMMAND variable elsewhere in your shell config;
that will break things.
==> Summary
🍺 /usr/local/Cellar/liquidprompt/1.11: 7 files, 125.6K, built in 3 seconds
[jeroenp:~/Versioned] 10s $
The Wiert Corner - irregular stream of stuff 