How to send an array using requests.post (Python)? "Value Error: Too many values to unpack"

Question

I'm trying to send an array(list) of requests to the WheniWork API using requests.post, and I keep getting one of two errors. When I send the list as a list, I get an unpacking error, and when I send it as a string, I get an error asking me to submit an array. I think it has something to do with how requests handles lists. Here are the examples:

url='https://api.wheniwork.com/2/batch'
headers={"W-Token": "Ilovemyboss"}
data=[{'url': '/rest/shifts', 'params': {'user_id': 0,'other_stuff':'value'}, 'method':'post',{'url': '/rest/shifts', 'params': {'user_id': 1,'other_stuff':'value'}, 'method':'post'}]
r = requests.post(url, headers=headers,data=data)
print r.text

# ValueError: too many values to unpack

Simply wrapping the value for data in quotes:

url='https://api.wheniwork.com/2/batch'
headers={"W-Token": "Ilovemyboss"}
data="[]" #removed the data here to emphasize that the only change is the quotes
r = requests.post(url, headers=headers,data=data)
print r.text

#{"error":"Please include an array of requests to make.","code":5000}

score 141 · Answer 1 · edited Feb 21 '16 at 11:16

You want to pass in JSON encoded data. See the API documentation:

Remember — All post bodies must be JSON encoded data (no form data).

The requests library makes this trivially easy:

headers = {"W-Token": "Ilovemyboss"}
data = [
    {
        'url': '/rest/shifts',
        'params': {'user_id': 0, 'other_stuff': 'value'},
        'method': 'post',
    },
    {
        'url': '/rest/shifts',
        'params': {'user_id': 1,'other_stuff': 'value'},
        'method':'post',
    },
]
requests.post(url, json=data, headers=headers)

By using the json keyword argument the data is encoded to JSON for you, and the Content-Type header is set to application/json.

causing less trouble than data=json.dumps(payload). Thanks for solution. — obayhan, Feb 28 '18 at 08:02

elad silver · Answer 2 · 2019-02-27T15:49:34.030

39

Well, It turns out that all I needed to do was add these headers:

headers = {'Content-Type': 'application/json', 'Accept':'application/json'}

and then call requests

requests.post(url,data=json.dumps(payload), headers=headers)

and now i'm good!

edited Feb 27 '19 at 15:49

answered Feb 21 '16 at 09:58

elad silver

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score 13 · Answer 3 · edited Jun 01 '18 at 00:50

Always remember when sending an array(list) or dictionary in the HTTP POST request, do use json argument in the post function and set its value to your array(list)/dictionary.

In your case it will be like:

r = requests.post(url, headers=headers, json=data)

Note: POST requests implicitly convert parameter's content type for body to application/json.

For a quick intro read API-Integration-In-Python

score 1 · Answer 4 · edited Dec 21 '21 at 21:58

I have a similar case but totally different solution, I've copied a snippet of code which looks like that:

resp_status, resp_data = requests.post(url, headers=headers, json=payload, verify=False)

and this resulted in error:

ValueError: too many values to unpack (expected 2)

just assigning to one variable resolve the issue:

response = requests.post(url, headers=headers, json=payload, verify=False)

How to send an array using requests.post (Python)? "Value Error: Too many values to unpack"

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