Crossbar.io : HTTP Bridge Services Caller : Sending signed requests correctly

Question

I am using crossbar HTTP bridge service caller to use a registered RPC. But when I issue the HTTP POST message, I get 'invalid request signature' as the response.

According to http://crossbar.io/docs/HTTP-Bridge-Services-Caller/, the

The signature computed as the Base64 encoding of the following value: HMAC[SHA256]_{secret} (key | timestamp | seq | nonce | body)

How to do the concatenation correctly? I tried both with and without character | and spaces.

section of the crossbar config.json file for signed requests:

        "call-signed": {
          "type": "caller",
          "realm": "realm1",
          "role": "anonymous",
          "options": {
            "key": "foobar",
            "secret": "secret",
            "post_body_limit": 0,
            "timestamp_delta_limit": 0,
            "require_ip": [
              "127.0.0.1"
            ],
            "require_tls": false,
            "debug": true
          }
        }

python code to send requests:

import hmac
import hashlib
import base64
import requests
import json

key = "foobar"
timestamp = "2011-10-14T16:59:51.123Z"
seq = "0"
nonce = "22"

# construct body
args = [1, 3, 2]
kwargs = None
options = None

proc = 'com.myapp.func'
payload = {"procedure": proc}

if args:
    payload['args'] = list(args)

if kwargs:
    payload['kwargs'] = dict(kwargs)

body = payload
body = json.dumps(body)

# construct signature
# (key | timestamp | seq | nonce | body)
message = key + "" + timestamp + "" + seq + "" + nonce + "" + body

print message

secret = "secret"

signature = base64.b64encode(hmac.new(secret, msg=message, digestmod=hashlib.sha256).digest())

print signature

# HTTP POST

url = "http://127.0.0.1:8080/call-signed?" + \
      "seq=" + seq + \
      "&key=" + key + \
      "&nonce=" + nonce + \
      "&signature=" + signature + \
      "&timestamp=" + timestamp

headers = {'content-type': 'application/json'}

s = requests.Session()
r = s.post(url, data=body, headers=headers)

print r.text

future visitors to this stack question should visit crossbar.io/docs/HTTP-Bridge instead of the posted URL which is no longer valid — FirefighterBlu3

Klanjabrik Klanjabrik · Accepted Answer · 2015-12-08T09:59:49

i'm using CrossbarHTTP https://github.com/thehq/python-crossbarhttp to handle HTTP bridge service, but if you insist to use your own code, you can check _compute_signature() method in this https://github.com/thehq/python-crossbarhttp/blob/master/crossbarhttp/crossbarhttp.py file, it might help you.

Crossbar.io : HTTP Bridge Services Caller : Sending signed requests correctly

1 Answers