Category: Developing & Application Integration

In this post I make my existing Python code re-runnable by enabling it to replace expired access tokens when it sends requests to the Strava API.

A couple of posts ago I wrote about authenticating Strava API calls. I ended up successfully requesting data using this Python code:

import requests

activities_url = "https://www.strava.com/api/v3/athlete/activities" 

header = {'Authorization': 'Bearer ' + "access_token"}
param = {'per_page': 200, 'page': 1}

my_dataset = requests.get(activities_url, headers=header, params=param).json()

print(my_dataset)

Although successful, the uses for this code are limited as it stops working when the header’s access_token expires. Ideally the code should be able to function constantly once Strava grants initial authorisation, which is what I’m exploring here. Plus the last post was unclear in places so this one will hopefully tie up some loose ends.

Please note that I have altered or removed all sensitive codes and tokens in this post in the interests of security.

The Story So Far

First of all, some reminders. Strava uses OAuth 2.0 for authentication, and this is a typical OAuth 2.0 workflow:

I am sending GET requests to Strava via Get Activity. Strava’s documentation for this is as follows:

Finally, during my initial setup I created an API Application on the Strava site. Strava provided these details upon completion:

Authorizing My App To View Data

Strava’s Getting Started page explains that they require authentication via OAuth 2.0 for data requests and gives the following link for that process:

http://www.strava.com/oauth/authorize?client_id=[REPLACE_WITH_YOUR_CLIENT_ID]&response_type=code&redirect_uri=http://localhost/exchange_token&approval_prompt=force&scope=read

I must amend this URL as scope=read is insufficient for Get Activity requests. The end of the URL becomes scope=activity:read_all and the updated URL loads a Strava authorization screen:

Selecting Authorize gives the following response:

http://localhost/exchange_token?state=&code=CODE9fbb&scope=read,activity:read_all

Where code=CODE9fbb is a single-use authorization code that I will use to create access tokens.

Getting Tokens For API Requests

Next I will use CODE9fbb to request access tokens which Get Activity will accept. This is done via the following cURL request:

curl -X POST https://www.strava.com/api/v3/oauth/token \
  -d client_id=APIAPP-CLIENTID \
  -d client_secret=APIAPP-SECRET \
  -d code=CODE9fbb \
  -d grant_type=authorization_code

Here, Client_ID and Client_Secret are from my API application, Code is the authorization code CODE9fbb and Grant_Type is what I’m asking for – Strava’s Authentication documentation states this must always be authorization_code for initial authentication.

Strava then responds to my cURL request with a refresh token, access token, and access token expiration date in Unix Epoch format:

"token_type": "Bearer",
  "expires_at": 1642370007,
  "expires_in": 21600,
  "refresh_token": "REFRESHc8c4",
  "access_token": "ACCESS22e5",

Why two tokens? Access tokens expire six hours after they are created and must be refreshed to maintain access to the desired data. Strava uses the refresh tokens as part of the access token refresh process.

Writing The API Request Code

With the tokens now available I can start assembling the Python code for my Strava API requests. I will again be using Visual Studio Code here. I make a new Python virtual environment called StravaAPI by running py -3 -m venv StravaAPI, activate it using StravaAPI\Scripts\activate and run pip install requests to install the module I need. Finally I create an empty StravaAPI.py file in the StravaAPI virtual environment folder for the Python code.

Onto the code. The first part imports the requests module, declares some variables and sets up a request to refresh an expired access code as detailed in the Strava Authentication documentation:

# Import modules
import requests


# Set Variables
apiapp_clientid = "APIAPP-CLIENTID"
apiapp_secret = 'APIAPP-SECRET'
token_refresh = 'REFRESHc8c4'

# Requesting Access Token
url_oauth = "https://www.strava.com/oauth/token"
payload_oauth = {
	'client_id': apiapp_clientid,
	'client_secret': apiapp_secret,
	'refresh_token': token_refresh,
	'grant_type': "refresh_token",
	'f': 'json'
}

Note this time that the Grant_Type is refresh_token instead of authorization_code. These variables can then be used by the requests module to send a request to Strava’s API:

print("Requesting Token...\n")
req_access_token = requests.post(url_oauth, data=payload_oauth, verify=False)
print(req_access_token.json())

This request is successful and returns existing tokens ACCESS22e5 and REFRESHc8c4 as they have not yet expired:

Requesting Token...

{'token_type': 'Bearer', 'access_token': 'ACCESS22e5', 'expires_at': 1642370008, 'expires_in': 20208, 'refresh_token': 'REFRESHc8c4'}

A warning is also presented here as my request is not secure:

InsecureRequestWarning: Unverified HTTPS request is being made to host 'www.strava.com'. Adding certificate verification is strongly advised.

The warning includes a link to urllib3 documentation, which states:

Making unverified HTTPS requests is strongly discouraged, however, if you understand the risks and wish to disable these warnings, you can use disable_warnings()

As this code is currently in development, I import the urllib3 module and disable the warnings:

# Import modules
import requests
import urllib3

# Disable Insecure Request Warnings
urllib3.disable_warnings()

Next I extract the access token from Strava’s response into a new token_access variable and print that in the terminal as a process indicator:

print("Requesting Token...\n")
req_access_token = requests.post(url_oauth, data=payload_oauth, verify=False)

token_access = req_access_token.json()['access_token']
print("Access Token = {}\n".format(token_access))

So far the terminal’s output is:

Requesting Token...

Access Token = ACCESS22e5

Let’s get some data! I’m making a call to Get Activities now, so I declare three variables to compose the request and include the token_access variable from earlier :

# Requesting Athlete Activities
url_api_activities = "https://www.strava.com/api/v3/athlete/activities"
header_activities = {'Authorization': 'Bearer ' + token_access}
param_activities = {'per_page': 200, 'page' : 1}

Then I use the requests module to send the request to Strava’s API:

print("Requesting Athlete Activities...\n")
dataset_activities = requests.get(url_api_activities, headers=header_activities, params=param_activities).json()
print(dataset_activities)

And receive data about several recent activities as JSON in return. Success! The full Python code is as follows:

# Import modules
import requests
import urllib3

# Disable Insecure Request Warnings
urllib3.disable_warnings()

# Set Variables
apiapp_clientid = "APIAPP-CLIENTID"
apiapp_secret = 'APIAPP-SECRET'
token_refresh = 'REFRESHc8c4'

# Requesting Access Token
url_oauth = "https://www.strava.com/oauth/token"
payload_oauth = {
	'client_id': apiapp_clientid,
	'client_secret': apiapp_secret,
	'refresh_token': token_refresh,
	'grant_type': "refresh_token",
	'f': 'json'
}

print("Requesting Token...\n")
req_access_token = requests.post(url_oauth, data=payload_oauth, verify=False)

token_access = req_access_token.json()['access_token']
print("Access Token = {}\n".format(token_access))

# Requesting Athlete Activities
url_api_activities = "https://www.strava.com/api/v3/athlete/activities"
header_activities = {'Authorization': 'Bearer ' + token_access}
param_activities = {'per_page': 200, 'page' : 1}
print("Requesting Athlete Activities...\n")
dataset_activities = requests.get(url_api_activities, headers=header_activities, params=param_activities).json()
print(dataset_activities)

But Does It Work?

This only leaves the question of whether the code works when the access code expires. As a reminder this was Strava’s original response:

Requesting Token...

{'token_type': 'Bearer', 'access_token': 'ACCESS22e5', 'expires_at': 1642370008, 'expires_in': 20208, 'refresh_token': 'REFRESHc8c4'}

Expiry 1642370008 is Sunday, 16 January 2022 21:53:28. I run the code at 22:05 and:

Requesting Token...

{'token_type': 'Bearer', 'access_token': 'ACCESSe0e7', 'expires_at': 1642392321, 'expires_in': 21559, 'refresh_token': 'REFRESHc8c4'}

A new access token! The new expiry 1642392321 is Monday, 17 January 2022 04:05:21. And when I run the code at 09:39:

{'token_type': 'Bearer', 'access_token': 'ACCESS74dd', 'expires_at': 1642433966, 'expires_in': 21600, 'refresh_token': 'REFRESHc8c4'}

A second new access code. All working fine! As long as my refresh token remains valid I can continue to get valid access tokens when they expire.

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Thanks for reading ~~^~~

Picking up from last time, I continued on with the Strava API Getting Started page and got myself very confused over how things were supposed to work. The Strava API requires authentication via OAuth 2.0, and in fairness Strava includes a graph that shows how the process works which unfortunately went right over my head. By chance I found a YouTube video produced by InterSystems Learning Services that gave me a good entry-level understanding of the process, boiling down to this slide:

As it turned out I was misunderstanding the purpose of the access token Strava was giving me on the My API Application page. That access token wasn’t provided by OAuth and so couldn’t be used to get any data – instead I needed to use Strava’s OAuth API to request different credentials and define a scope for the access needed.

To that end, Strava provides this link on their Getting Started page:

http://www.strava.com/oauth/authorize?client_id=[REPLACE_WITH_YOUR_CLIENT_ID]&response_type=code&redirect_uri=http://localhost/exchange_token&approval_prompt=force&scope=read

Which was used in conjunction with my app’s ClientID to get an authorization code in the form of:

http://localhost/exchange_token?state=&code=MYAUTHCODE123456789&scope=read

Next, a cURL request must be made to exchange the authorization code and scope for a refresh token, access token, and access token expiration date. The page suggests https://www.strava.com/oauth/token which turns out to be wrong – the URL used in the Authentication documentation for this is https://www.strava.com/api/v3/oauth/token. At this point I was having varying success with Postman, so instead installed REST Client on Visual Studio Code on the advice of Vu Long Tran’s blog which made things much simpler.  

Sending a request of:

curl -X POST https://www.strava.com/api/v3/oauth/token 

  -d client_id=ReplaceWithClientID \

  -d client_secret=ReplaceWithClientSecret \

  -d code=ReplaceWithCode \

  -d grant_type=authorization_code\

Produced a response containing my Strava profile data along with new tokens and details of their expiry:

"token_type": "Bearer"

"expires_at": 1640810729,

"expires_in": 4002,

"refresh_token": REFRESHTOKEN123456789

"access_token": "ACCESSTOKEN123456789"

Awesome! Now to put these to work…

Part of my confusion coming into this was that I had been given a Python script in my travels that I was expecting to work with the access token from the My API Application screen, which of course with the benefit of hindsight was never going to be successful. The Python script is as follows:

import requests

activities_url = "https://www.strava.com/api/v3/athlete/activities"

header = {'Authorization': 'Bearer ' + "access_token"}
param = {'per_page': 200, 'page': 1}

my_dataset = requests.get(activities_url, headers=header, params=param).json()

print(my_dataset)

Time to test it out with the new access token! Straight into a problem:

{'message': 'Authorization Error', 'errors': [{'resource': 'Athlete', 'field': 'access_token', 'code': 'invalid'}]}

The Strava API and SDK Reference page was quick to indicate the source of the problem:

The previous requests to Strava’s OAuth API were with scope=read. I changed this to scope=activity:read_all and received a new authorization code with the updated scope. This authorization code was then exchanged for a new access token which, when pasted into the Python script, outputted so much JSON that in the interests of sanity I’ve screenshotted a small section for illustration:

To be fair it was what I asked for. And it all makes a bit more sense to me now!

Future plans for this involve making use of the refresh tokens to automate access token generation (assuming I’ve understood that part correctly – stay tuned!) and getting some working code into a Lambda function so I can start turning some cogs in AWS.

Thanks for reading ~~^~~