Get zabbix graph to png via API - bash

Question

I have a login script as follows:
curl --location --request POST 'https://zabbixUrl.com/api_jsonrpc.php' \
--header 'Authorization: Basic bWlndWVsLmh1cnRhZG86MTczM295ZmQxVg==' \
--header 'Content-Type: application/json' \
--data-raw '{
"jsonrpc": "2.0",
"method": "user.login",
"params": {
"user": "user",
"password": "pass"
},
"id": 1
}'
Which returns:
{"jsonrpc":"2.0","result":"1g1hd43j4d3jd4jsl4n35b4211n1d2e2","id":1}
With this Api token (result), I can execute all the Zabbix's methods, for instance:
curl --location --request POST 'https://zabbixUrl.com/api_jsonrpc.php' \
--header 'Authorization: Basic bWlndWVsLmh1cnRhZG86MTczM295ZmQxVg==' \
--header 'Content-Type: application/json' \
--data-raw '
{
"jsonrpc": "2.0",
"method": "screenitem.get",
"params": {
"output": "extend",
"screenids": "258"
},
"auth": "1g1hd43j4d3jd4jsl4n35b4211n1d2e2",
"id": 1
}'
Now I am trying to obtain a graph in PNG format. I can view this graph in PNG format after inserting the user and pass in the intermediate screen:
Now what I am trying to do is to get this PNG graph via API. My approach is the following (ps: the url included is the same one as the one used on the browser, where it does work):
curl --header 'Authorization: Basic bWlndWVsLmh1cnRhZG86MTczM295ZmQxVg==' --data-raw 'auth:1g1hd43j4d3jd4jsl4n35b4211n1d2e2' http://zabbixUrl.com/chart2.php?graphid=123456&period=604800&stime=1614012539
Using this form, I get a 401 error. I guess that it is not correctly detecting the token.
Therefore, my question is, how can I obtain the PNG of this Zabbix's graph via API? How can I do it so it correctly detects the token?

Answer 1

When you authenticate to the API you use a token, when you authenticate to the GUI you need a cookie. Using curl, you need the --cookie option, see Save cookies between two curl requests.
In python requests, you would use a Session: see zabbix-gnomes's zgetgraph.py for a python solution.
A working example in Zabbix 5.0:
auth=$(curl -s --data '{ "jsonrpc": "2.0", "method": "user.login", "params": { "user": "...", "password": "..." }, "id": 1 }' --header 'Content-Type: application/json' https://.../zabbix/api_jsonrpc.php | jq -r .result)
curl --cookie "zbx_sessionid=$auth" "https://.../zabbix/chart2.php?graphid=517&from=now-2d&to=now&height=201&width=1717&profileIdx=web.charts.filter&_=up0bkgs0" -o file.png

Answer 2

I found the solution:
import requests
import json
import shutil
​
##### GET CREDENTIALS #####
​
USER = "user"
PASSWORD = "pass"
URL_AUTH = "https://url.com/api_jsonrpc.php"
HEADER_AUTH = {
'Authorization': 'Basic bWlndWVsLmh1cnRhZG86MTczM295ZmQxVg==',
'Content-Type': 'application/json',
}
DATA_AUTH = """
{
"jsonrpc": "2.0",
"method": "user.login",
"params": {
"user": "%s",
"password": "%s",
"userData": true
},
"id": 1
}
""" % (USER, PASSWORD)
respAuth = requests.post(URL_AUTH, headers=HEADER_AUTH, data=DATA_AUTH)
zabbixSessionId = json.loads(respAuth.content.decode('utf8').replace("'", '"'))["result"]["sessionid"]
##### GET PNG #####
URL_CHART = "https://url.com/chart2.php?graphid=12345&period=7200"
HEADER_CHART = {
'Authorization': 'Basic bWlndWVsLmh1cnRhZG86MTczM295ZmQxVg==',
'Content-Type': 'image/png',
'Cookie': 'zbx_sessionid=%s' % (zabbixSessionId)
}
PNG_PATH = "./image.png"
respChart = requests.request("POST", URL_CHART, headers=HEADER_CHART, stream=True)
with open(PNG_PATH, 'wb') as out_file:
shutil.copyfileobj(respChart.raw, out_file)