json连接到request.post python

Question

I'm measuring temperature and humidity from a sensor. I want then to post the measures to a server as json strings. I'm using a python script.

For optimisation, I want to group the json strings and post them.

My code is like this:

current_time = time.localtime()[0:6]
date = dateformat % current_time[0:6]
temp = str(round(temp, 1))
hum = str(round(hum, 1))

lastest_measure = {'UID': uuid, 'date': date, 'temperature': temp, 'humidity': hum}
r = requests.post(url, data=json.dumps(lastest_measure), headers=headers)
print r

>>> response 200: Good !

But I can't concatenate the lastest_measure to a grouped_measure .

I tried to concatenate with

grouped_measure = dict(group_measure.items() + lastest_measure.items())

but it gives me an error:

"AttributeError: 'dict' object has no attribute 'item'"

I tried to create a string with all the measure (in the correct format, ie: [{...},{...}, ...] and then use the json.dumps

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

But I get an error 500 (because the format doesn't inclue the '' between all the values)

So my question is how can I concatenate 2 dictionaries in the right format for the resquest.post method ? (is it a method ???)

Thanks in advance ! Cheers, Mat

Answer 1

The problem is, the POST request is expecting a JSON format, which is essentially like a Python dictionary, only it accepts only specific types and requires the keys to be strings.

This means, if you are doing a time series, and have the same keys in a dictionary from many dictionaries, like a Python dictionary, it will override the given values. In short, there is no way to solve the problem using a single POST request for a website that accepts JSON data.

To solve this, you can use iteration.

Here's an arbitrary example, but works for your example:

Step 1: Get the dictionaries (which you already have) and create a Python list from them.

# arbitrary case
dicts = []
for num in range(20):
    mydict = {i: i**num for i in range(50)}
    dicts.append(mydict)

Now that I have my dictionaries, I can then iterate over them to post the request.

import json
# iterate
for mydict in dicts:
    json_string = json.dumps(mydict)
    r = requests.post(url, data=json_string, headers=headers)

Now, if you can define the dictionaries and post the requests at the same time, this code will be much more efficient.

Answer 2

I got this solution:

data = [ ]
def add_DataSet(field1, field2, field3, field4):
     global data
     data.append({"field1":var1, "filed2":var2, "field3":var3, "field4":var4})

then

add_DataSet(field1, field2, field3, field4)

It works perfect with the

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