How to fetch an attribute value from a variable, having the content of a JSON response - json

Question

I'm using the Robot Framework API automation. Here, storing the JSON response in a variable [POSTResp.content]. I.e., "POSTResp.content" has the whole response, as given below. Please help me to get an attribute's value (for ex, value of referenceId) from the stored content.
Example of JSON response:
{
"serviceResponseHeader": {
"responseContext": {
"responseCode": "MS19",
"responseDescription": "Success",
"serviceResponseTimeInGMT": "18 Sep 2018 16:12:43 GMT"
},
"requesterContext": {
"applicationCode": null,
"applicationSubCode": null,
"countryCode": null,
"requesterReferenceNumber": null,
"requestTimeInGMT": "30 Jun 2015 11:54:49 GMT",
"requesterUserIdentity": "23483",
"requesterGroupIdentity": "1620",
"requesterIpAddress": "",
"sessionIdentity": "2536kjhfdashfkhfsab",
"ssoSessionIdentity": "2536kjhfdashfkhfsab",
"requesterAbbreviatedGroupName": "NEWCOMP"
},
"serviceContext": {
"serviceVersionNumber": "1.0",
"serviceCode": "30"
}
},
"getProxyDetailResponseBody": {
"proxyDetails": {
"proxyType": "",
"proxyValue": "20140005K",
"referenceId": "PR18090000847597",
"transactionId": "18091801657466"
}
}
}
I've tried the below ways,
1) ${json} To JSON ${POSTResp.content} true
log to console \n the Proxy ID is ${json["proxyValue"]}
Result: Resolving variable '${json["proxyValue"]}' failed: TypeError: string indices must be integers, not str
2) ${json} Evaluate json.loads(${POSTResp.content}} json
log to console \n the Proxy ID is ${json["proxyValue"]}
Result: failed: SyntaxError: unexpected EOF while parsing (, line 1)

Answer 1

Issues with your two approaches:
1) the library keyword call passes a true argument (well, truth-like) to the pretty_print parameter:
${json} To JSON ${POSTResp.content} true
Looking at the library's source, in that case the keyword does not return a dict object - but a string, a beatified version of the source json. That coincides with the error your received.
Remove the "true" argument and it must return a dict.
2) In the Evaluate surround the variable with triple quotes (python's literal string):
${json} Evaluate json.loads('''${POSTResp.content}'''}
json
Without it, the framework just dumped the variable's value, which raised a python syntax error.
By the way, try not to make your variables with language keywords/library names - like ${json} up there.