How to deal with HTTP 102 in bash? - bash

Question

From bash/curl I am consuming an API that receives a POST, perform heavy long tasks and returns a 200 on success. As we were facing some timeouts in WAF, API has been improved to accept header:
--header "Expect:102-Processing"
If API receives that header it sends a HTTP 102 every 20 secs until process finishes and sends a HTTP 200. This should be enough to prevent timeouts.
What I have to do to deal with those HTTP 102?
I added that header to my curl command but as soon as it receives first 102, curl command finishes.
I was thinking that maybe there is a parameter in curl to wait until 200 or error.
Another option I have in mind is waiting in a loop querying for status but I don't know how to instruct curl to monitor that connection
This is a test version of my bash script.
#!/bin/bash
clear
function_triggerFooAdapter()
{
pFooUrl=$1
pPayload=$2
pCURLConnectTimeout=$3
pWaitForFooResponse=$4
pAddExpect102Header=$5
rm ./tmpResult.html 2>/dev/null
rm ./tmpResult.txt 2>/dev/null
echo "Triggering internal Foo adapter $pFooAdapterName"
echo "Full URL=$pFooUrl"
echo "Payload to send=$pPayload"
echo "Curl connect-timeout=$pCURLConnectTimeout"
echo "WaitForFooResponse=$pWaitForFooResponse"
echo "AddExpect102Header=$pAddExpect102Header"
if [[ "$pAddExpect102Header" = true ]]; then
text102Header="Expect:102-Processing"
else
text102Header="NoExpect;" # send innofensive custom header
fi
if [[ "$pWaitForFooResponse" = true ]]; then
echo "So DO wait..."
Response=$(curl -k --write-out %{http_code} --header "$text102Header" --header "Content-Type:application/json" --silent --connect-timeout $pCURLConnectTimeout --output ./tmpResult.html -X POST --data "$pPayload" "$pFooUrl" 2>&1 | tee ./tmpResult.txt)
echo "HTTP Response=$Response"
echo "$(cat ./tmpResult.txt)"
if [ "${Response:0:1}" -eq "1" ] || [ "${Response:0:1}" -eq "2" ]; then #if HTTP Response start by 1 or 2 (10x - 20x)...
echo "Adapter sucessfully triggered."
return 0
else
# cat ./tmpResult.html 2>/dev/null
#cat ./tmpResult.txt 2>/dev/null
echo
echo "HTTP error trying to trigger adapter."
return 1
fi
else
echo "So DO NOT wait..."
curl -k --write-out %{http_code} --header "$text102Header" --header "Content-Type:application/json" --silent --connect-timeout $pCURLConnectTimeout --output ./tmpResult.html -X POST --data "$pPayload" "$pFooUrl" > /dev/null 2>&1 &
echo "Adapter sucessfully (hopefully) triggered. NOT reading HTTP response until Foo code is upgraded to respond directly a HTTP 200 Successfully queued or similar."
return 0
fi
}
clear
export http_proxy="http://1.1.1.256:3128/"
export https_proxy="http://1.1.1.256:3128/"
export no_proxy="foo.com"
# Main
clear
echo "STEP 09- Triggering Foo Internal Adapters."
echo "Proxy settings:"
env | grep proxy
function_triggerFooAdapter "http://foo.com/lookups/trigger_foo" "" 600 true true

Answer 1

Run it manually and CHECK what curl -v is sending as the headers; I would expect to see something like
> POST /the/url HTTP/1.1
> Host: thehost.com:80
> User-Agent: curl/7.51.0
> Accept: */*
> Expect: 102-Processing
... some stuff skipped.
If you're not sending the Expect header; then curl is in fact doing the right thing..