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Using websocat to perform a CLI request using websockets to a hasura engine
#! /usr/bin/bash
# Using WebSocat
# https://github.com/vi/websocat/blob/master/moreexamples.md
# Reset by killing process
#
# 1. Get all processes
# 2. general regexp to find websocat process di
# 3. Get the second column of results
# 4. Get the first result
# 5. Kill that process
#
# kill $(ps aux | grep websocat | awk '{print $2}' | head -n 1)
# Configuration
TARGET_URL=wss://yourgraphql.com/v1/graphql
LOCALHOST=127.0.0.1
LOCALPORT=6543
# Absolute path to websocat
CMD=~/Downloads/websocat.x86_64-unknown-linux-musl
# Parameters used
# -t Send message to WebSockets as text messages
# tcp-l Listen TCP port on specified address
# -E Close a data transfer direction if the other one reached EOF
# reuse-raw
# --max-messages-rev Maximum number of messages to copy in the other direction
echo " ⏳️ Connecting to WebSocat..."
${CMD} -t -E tcp-l:${LOCALHOST}:${LOCALPORT} reuse-raw:${TARGET_URL} --max-messages-rev 2&
# Store websocket process id
WS_PID=$!
echo " 🚀 Websocat connection created (${WS_PID})!"
TABLE_NAME="accounts"
HASURA_ADMIN_SECRET="somesecret"
# Send message to websocat
echo " 🌏️ Initiating Hasura graphql subscription..."
echo "{ \"type\": \"connection_init\", \"payload\": { \"headers\": { \"X-Hasura-Admin-Secret\": \"${HASURA_ADMIN_SECRET}\", \"BP-Customer-IP-Address\": \"127.0.0.1\" } } }" | nc ${LOCALHOST} ${LOCALPORT}
echo " 🌏️ Requesting three accounts from the account service..."
echo "{ \"id\": \"1\", \"type\": \"start\", \"payload\": { \"variables\": {}, \"extensions\": {}, \"operationName\": \"GetThreeAccounts\", \"query\": \"query GetThreeAccounts { ${TABLE_NAME}(limit: 3) { id } }\" } }" | nc ${LOCALHOST} ${LOCALPORT} | jq
echo '{"id":"1","type": "stop"}' | nc ${LOCALHOST} ${LOCALPORT} | jq
echo " ✅ Done!"
echo " 🗑️ Websocat connection disposed."
kill ${WS_PID}
@darrensapalo
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darrensapalo commented Jul 7, 2022

Sample Result

image

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