I am working with a cloud-based service that is exposed using OAuth REST API.
I have a working Python script, with which I am able to first post username, password and api token to get an authentication token. Then I use the api and authentication tokens to get data. Here is my Python script:
import requests
base_url = 'https://example.com'
user_name = 'john_doe'
password = 'pssw0rd'
api_token = '4r-eueyta-dh7cuq-26'
timeout_min = 1
headers = {'Accept': 'application/json'}
# get authentication token
auth_url = base_url + '/api/authenticate'
data = {'Username': user_name,
'Password': password,
'ApiToken': api_token,
'AuthorizationTokenTimeoutMinutes': timeout_min}
r = requests.post(auth_url, headers=headers, data=data)
# the entire string response is the auth token
auth_token = r.text
# get data
proj_url = base_url + '/api/project/active?' + \
'api-token={0}&authentication-token={1}'.format(api_token, auth_token)
r = requests.get(proj_url, headers=headers)
print(r.text)
This is working fine.
Next I want to use the same approach inside Microsoft Power BI to configure this data as a data source. I followed the approach outlined at http://angryanalyticsblog.azurewebsites.net/index.php/2016/05/16/api-strategies-with-power-bi/
As mentioned in the post, I set the variables
- base_url
- user_name
- password
- api_token
- auth_token_timeout_min
as parameters and set their values. Then got the following power query script in advanced editor:
let
// get auth token
auth_url = #"base_url" & "/api/authenticate",
post_data = "Username=" & #"user_name" & "&Password=" & #"password" & "&ApiToken=" & #"api_token" & "&AuthorizationTokenTimeoutMinutes=" & #"auth_token_timeout_min",
AuthJsonQuery = Web.Contents(auth_url,
[Headers = [#"Accept"="application/json"],
Content = Text.ToBinary(post_data)]),
auth_token = Json.Document(AuthJsonQuery),
// get data
proj_url = #"base_url" & "/api/project/active?api-token=" & #"api_token" & "&authentication-token=" & auth_token,
GetJsonQuery = Web.Contents(proj_url,
[Headers = [#"Accept"="application/json"]]),
FormatAsJsonQuery = Json.Document(GetJsonQuery),
in
#"FormatAsJsonQuery"
This script gives the following error:
DataSource.Error: Web.Contents failed to get contents from 'https://example.com/api/authenticate' (415): Unsupported Media Type
Details:
DataSourceKind=Web
DataSourcePath=https://example.com/api/authenticate
Url=https://example.com/api/authenticate
The raw response from the first POST request is exactly the authentication token and I am missing something in correctly decoding it.
If I manually configure the authentication token directly in proj_url then I am able to get the data, so I am doing something wrong with getting the authentication token.
UPDATE:
My goal was to somehow make the data available inside Power BI. I took an alternative approach with using R as a data source. (You will need to install R and the httr package in R for this.) Posting that solution here:
library(httr)
base_url <- 'https://example.com'
user_name <- 'john_doe'
password <- 'pwws0rd'
api_token <- '4r-eueyta-dh7cuq-26'
timeout_min <- 1
# get authentication token
auth_url <- paste0(base_url, '/api/authenticate')
data <- list('Username' = user_name,
'Password' = password,
'ApiToken' = api_token,
'AuthorizationTokenTimeoutMinutes' = timeout_min)
resp <- POST(auth_url,
body = data,
encode = 'json')
auth_token <- content(resp, "parsed", "application/json")
# get data
proj_url <- paste0(base_url, '/api/project/active?',
'api-token=', api_token,
'&authentication-token=', auth_token)
resp <- GET(proj_url, encode = 'json')
# convert the response to data frame
results <- content(resp, "parsed", "application/json")
results <- lapply(results, function(x) {
x[sapply(x, is.null)] <- NA
unlist(x)})
projects <- do.call("rbind", results) # matrix
projects <- data.frame(projects, stringsAsFactors = FALSE)
projects is then available for importing into Power BI.
