Problem with: Template (JSON) > Exec (Python) > Payload (Output)

General
1

I'm having some trouble injecting JSON into a Python script being executed using the Exec node. The JSON is held in a template node. I've read all the other forum posts on this and similar but I am still hitting a dead end. The Flow JSON and (very simple) Python script are below.

Any help to resolve this would be most gratefully received :heart:.

The flow JSON:

[
    {
        "id": "7f8485d6fdbb1016",
        "type": "tab",
        "label": "Syspro Business Objects",
        "disabled": false,
        "info": "",
        "env": []
    },
    {
        "id": "72ba41ac93f463b6",
        "type": "inject",
        "z": "7f8485d6fdbb1016",
        "name": "Inject",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "",
        "payloadType": "date",
        "x": 170,
        "y": 160,
        "wires": [
            [
                "432ef353974e0f43"
            ]
        ]
    },
    {
        "id": "3dc73cd34e6c9e81",
        "type": "debug",
        "z": "7f8485d6fdbb1016",
        "name": "",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "payload",
        "targetType": "msg",
        "statusVal": "",
        "statusType": "auto",
        "x": 770,
        "y": 160,
        "wires": []
    },
    {
        "id": "7c06188252ebc2f3",
        "type": "exec",
        "z": "7f8485d6fdbb1016",
        "command": "python D:\\Python\\Syspro\\SORQRY.py ",
        "addpay": "payload",
        "append": "",
        "useSpawn": "false",
        "timer": "",
        "winHide": false,
        "oldrc": false,
        "name": "SORQRY",
        "x": 580,
        "y": 160,
        "wires": [
            [
                "3dc73cd34e6c9e81"
            ],
            [
                "3dc73cd34e6c9e81"
            ],
            [
                "3dc73cd34e6c9e81"
            ]
        ]
    },
    {
        "id": "432ef353974e0f43",
        "type": "template",
        "z": "7f8485d6fdbb1016",
        "name": "SORQRY_params",
        "field": "payload",
        "fieldType": "msg",
        "format": "json",
        "syntax": "mustache",
        "template": "{\n   \"Key\":{\n      \"SalesOrder\":\"000231\"\n   },\n   \"Options\":{\n      \"DatabaseLetter\":\"T\",\n      \"OutputFormat\":\"JSON\",\n      \"IncludeStockedLines\":\"Y\",\n      \"IncludeNonStockedLines\":\"Y\",\n      \"IncludeFreightLines\":\"Y\",\n      \"IncludeMiscLines\":\"Y\",\n      \"IncludeCommentLines\":\"Y\",\n      \"IncludeCompletedLines\":\"Y\",\n      \"IncludeSerials\":\"N\",\n      \"IncludeLots\":\"Y\",\n      \"IncludeBins\":\"Y\",\n      \"IncludeAttachedItems\":\"N\",\n      \"IncludeCustomForms\":\"Y\",\n      \"IncludeDetailLineCustomForms\":\"Y\",\n      \"IncludeValues\":\"N\",\n      \"ReturnLineShipDate\":\"N\"\n   }\n}",
        "output": "json",
        "x": 370,
        "y": 160,
        "wires": [
            [
                "7c06188252ebc2f3"
            ]
        ]
    }
]

The Python script:

import json
import sys

# read json payload from first commend line parameter
json_payload = sys.argv[1:]
data_dict = json_payload.json()

key_SalesOrder                      = data_dict["Key"]["SalesOrder"]

option_DatabaseLetter               = data_dict["Options"]["DatabaseLetter"]
option_OutputFormat                 = data_dict["Options"]["OutputFormat"]

print("{")
print("   'Key': '" + key_SalesOrder + "'," )
print("   'DatabaseLetter': '" + option_DatabaseLetter + "'" )
print("}")
3

What do you see in msg.payload if you feed that into a debug node?

4

If I add a debug node to the output of the Template then I get the full JSON held in the Template node. If the setting is Output as 'Plain TExt' then I get a string and if set to 'Formatted JSON' I get a JSON array out

5

What command, entered in a command window, are you trying to replicate in the exec node? Something like
python D:\Python\Syspro\SORQRY.py param1 param2 ...

6

Hi Colin, yes that's exactly what I'm trying to do, pass the JSON payload in as param1 (in your example)

7

Please show us an exact example command that works in the command line but not in node-red

8

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