Develop Reference

POST request to FastAPI using Python Requests with a file and query parameters

I am using FastAPI to serve some ML models and I have a Streamlit basic UI using Python Requests module.
One of my service is getting an image through a POST request and it is working like a charm.
Server side
#app.post("/segformer")
async def segformer(file: Optional[UploadFile] = None):
curl given by {BASE_URI}/docs
curl -X 'POST' \
'http://localhost:8080/segformer' \
-H 'accept: application/json' \
-H 'Content-Type: multipart/form-data' \
-F 'file=#image1.jpg;type=image/jpeg'
Client side using Python Requests
response = requests.post(f"{BASE_URI}/segformer", files=files)
As soon as I want to add additional parameters, it gets creepy. For example:
Server side
#dataclass
class ModelInterface:
model_name: str = "detr"
tags: List[str] = Query(...)
#app.post("/detr")
async def detr(file: UploadFile = File(...), model: ModelInterface = Depends()):
curl -- given by {BASE_URI}/docs
curl -X 'POST' \
'http://localhost:8080/detr?model_name=detr&tags=balloon&tags=dog' \
-H 'accept: application/json' \
-H 'Content-Type: multipart/form-data' \
-F 'file=#image1.jpg;type=image/jpeg'
Until that point everything works fine. Once I want to convert that call using Python Requests, I have some issues, which always end up in /detr HTTP/1.1" 400 Bad Request error.
Here is what I've tried:
Client side using Python Requests
headers = {
"Content-type": "multipart/form-data",
"accept": "application/json"
}
payload = {
"tags": ["balloon", "dog"]
}
response = requests.post(
f"{BASE_URI}/detr",
headers=headers,
json=payload, <- also *data*
files=files,
)
At the end it seems that the problem narrows on how to convert this:
curl -X 'POST' \
'http://localhost:8080/detr?tags=balloon&tags=dog' \
-H 'accept: application/json' \
-H 'Content-Type: multipart/form-data' \
-F 'file=#image1.jpg;type=image/jpeg'
to a valid Python Requests call!
I also faced the issue that the following FastAPI code:
#dataclass
class ModelInterface:
model_name: str = "detr"
tags: List[str] = None
#app.post("/detr2")
async def detr2(file: UploadFile = File(...), model: ModelInterface = Form(...)):
...
translates to this curl command:
curl -X 'POST' \
'http://localhost:8080/detr2' \
-H 'accept: application/json' \
-H 'Content-Type: multipart/form-data' \
-F 'file=#image1.jpg;type=image/jpeg' \
-F 'model={
"model_name": "detr",
"tags": [
"balloon", "dog"
]
}'
which fails with a "POST /detr2 HTTP/1.1" 422 Unprocessable Entity error

To pass query parameters in Python requests, you should use params key instead. Hence:
response = requests.post(url='<your_url_here>', params=payload)
Additionally, there is no need to set the Content-type in the headers, as it will automatically be added, based on the parameters you pass to requests.post(). Doing so, the request will fail, as, in addition to multipart/form-data,"Content-type must include the boundary value used to delineate the parts in the post body. Not setting the Content-Type header ensures that requests sets it to the correct value" (ref). Have a look at this and this. Also, make sure that in files you use the same key name you gave in your endpoint, i.e., file. Thus, in Python requests it should look something like the below:
files = {('file', open('my_file.txt', 'rb'))}
response = requests.post(url='<your_url_here>', files=files, params=payload)
You could also find more options as to how to send additional data along with files at this answer.

Convert cURL command Into Python using requests

I am trying to convert the following cULR command into Python:
curl --location --request POST 'api.datamyne.com/frontend/REST/application' \
--header 'Content-Type: application/json' \
--data-raw '{
"token": "boKnofR06mzldz5eL00ARwa3B9winzpn",
"idApp":44
}'
I have the following Python code, but does not seem to work. Any idea how to include the raw data into into the request?
import requests
headers = {
'Content-Type': 'application/json',
'token': 'boKnofR06mzldz5eL00ARwa3B9winzpn',
'idApp': '44'
}
response = requests.get('http://api.datamyne.com/frontend/REST/applications', headers=headers)
print(response.content)

So in your python example you have called request.get().
If you call request.post() it will instead become a POST request.
as for adding it to the body, you could try a body variable:
data = {
'token': 'boKnofR06mzldz5eL00ARwa3B9winzpn',
'idApp': '44'
}
response = requests.post('http://api.datamyne.com/frontend/REST/applications',
headers=headers,
data = data)
Update:
This still fails because of an incorrectly formatted body.
to fix this i imported the json package and wrote:
#load string into a json object
data = json.loads('{"token": "boKnofR06mzldz5eL00ARwa3B9winzpn", "idApp": 44 }')
# json.dumps outputs a json object to a string.
response = requests.post('https://api.datamyne.com/frontend/REST/application', headers=headers, data=json.dumps(data))

Python post request returns 500

I am using requests to make a POST request to create a user. The request succeeds with 201 created when I use curl, however fails with a 500 response when I use requests. My curl command is
curl --user administrator:password -H "Content-Type: application/json" https://localhost:8080/midpoint/ws/rest/users -d #user.json -v
And my python script is:
import requests
import json
headers = {
'Content-Type': 'application/json',
}
with open('user.json') as j:
data = json.load(j)
response = requests.post('https://localhost:8080/midpoint/ws/rest/users', headers=headers, data=str(data), auth=('Administrator', 'password'))
print(response)
Can anyone see a reason why my python script would be failing? I am at a loss.

str(data) returns the Python representation of data, not its JSON representation. These two forms can differ in things like ' vs. ", True vs. true, and None vs. null. To properly JSONify data, call json.dumps() on it:
response = requests.post(..., data=json.dumps(data))
or let requests do the JSONification:
response = requests.post(..., json=data)
or use the JSON as it appears in user.json directly:
with open('user.json') as j:
data = j.read()
response = requests.post(..., data=data)

Convert curl to Pycurl.

I have this curl command and I would like to know if I have converted it correctly to pycurl.
curl command
curl -D- -u fred:fred -X PUT --data{see below} -H "Content-Type:application/json" http://kelpie9:8081/rest/api/2/issue/QA-31
{
"fields":
{
"assignee":{"name":"harry"}
}
}
python code
def assign(self, key, name):
data = json.dumps({"fields":{"assignee":{"name":name}}})
c= pycurl.Curl()
c.setopt(pycurl.VERBOSE, 1)
c.setopt(pycurl.URL, "http://xxx/rest/api/2/issue/"+ key )
c.setopt(pycurl.HTTPHEADER, ['Content-Type: application/json', 'Accept: application/json'])
c.setopt(pycurl.USERPWD, "****")
c.setopt(pycurl.PUT, 1)
c.setopt(pycurl.POSTFIELDS,data)
c.perform(

Nopes. First off: use curl's --libcurl option to get a first template.
Then, "-X PUT" translates to CUSTOMREQUEST set to "PUT", only changing the actual method keyword.

I would personally accomplish this by using the remarkable requests library
import requests
import requests.auth
import json
def assign(key, name):
url = "http://xxx/rest/api/2/issue/" + key
headers = {'Content-type': 'application/json', 'Accept': 'application/json'}
data = json.dumps({"fields": {"assignee": {"name": name}}})
r = requests.put(url, data=data, headers=headers, auth=requests.auth.HTTPBasicAuth('fred', 'fred'))
print(r.status_code)
print(r.json())

curl -j --libcurl git.txt -D- -u fred:fred -X PUT --data"{\"fields\":{\"assignee\":{\"name\":\"FRED\"}}}" -H "Content-Type:application/json" http://kelpie9:8081/rest/api/2/issue/QA-31
this gives the template in git.txt .
Also in the data field the inner quotes must be escaped as shown above.
The working code is attached below.
def assign(self, key, name):
self._startCurl()
self.c.setopt(pycurl.URL, "http://xxx/rest/api/2/issue/"+ key )
self.c.setopt(pycurl.HTTPHEADER, ['Content-Type: application/json', 'Accept: application/json'])
self.c.setopt(pycurl.USERPWD, "fred:fred")
self.c.setopt(pycurl.CUSTOMREQUEST, "PUT")
data = json.dumps({"fields":{"assignee":{"name":name}}})
self.c.setopt(pycurl.POSTFIELDS,data)
self.c.perform()
self.c.close()
Thanks to Daniel Stenberg for pointing it out

How to make a post request with REQUESTS package for Python?

I am trying to use the toggl api.
I use Requests instead of Urllib2 for doing my GETs en POSTS. But i am stuck.
payload = {
"project":{
"name":"Another Project",
"billable":False,
"workspace":{
"Name":"jorrebor's workspace",
"id":213272
},
"automatically_calculate_estimated_workhours":False
}
}
url = "https://www.toggl.com/api/v6/projects.json"
r = requests.post(url, data=json.dumps(payload), auth=HTTPBasicAuth('j_xxxxx#gmail.com', 'mypassword'))
Authentication seems to be fine, but the payload format probably isn't.
a curl command with the same parameters:
curl -v -u heremytoken:api_token -H "Content-type: application/json" -d "{\"project\":{\"billable\":true,\"workspace\":{\"id\":213272},\"name\":\"Another project\",\"automatically_calculate_estimated_workhours\":false}}" -X POST https://www.toggl.com/api/v6/projects.json
does work fine.
What wrong with my payload? The response is get is:
["Name can't be blank","Workspace can't be blank"]
which leads me to conclude that the authentication works but toggl cannot read my json object.

Seems like you should try setting the header to a JSON application, rather than the default format, and send a JSON object instead of the Python dict. Check it out here:
payload = {"project":{"name":"Another Project",
"billable":False,
"workspace":{"Name":"jorrebor's workspace",
"id":213272},
"automatically_calculate_estimated_workhours":False
} }
parameters_json = json.dumps(payload)
headers = {'Content-Type': 'application/json')
r = client.post(url, data=parameters_json, headers=headers)
which should allow the site to read the json object just fine.