Why is R HTTR content statement not producing the expected request body?

Question

I am using R to call on Cybersource API. When I use the GET request I obtain a successful response of 200. When I read the body of the the response rather than get the csv data back I get a path to a csv file path. I wonder what I am doing wrong.

content(request) gives

 "/space/download_reports/output/dailyreports/reports/2018/10/27/testrest/TRRReport-7931d82d-cf4a-71fa-e053-a2588e0ab27a.csv"

The result of content(request) should be the data not a file path.

Here is a the code

library('httr')
merchant<-'testrest'
vcdate<-'Wed, 29 May 2019 10:09:48 GMT'
ho<-'apitest.cybersource.com'
URL<-'https://apitest.cybersource.com/reporting/v3/report-downloads?organizationId=testrest&reportDate=2018-10-27&reportName=TRRReport'
sign<-'keyid="08c94330-f618-42a3-b09d-e1e43be5efda", algorithm="HmacSHA256", headers="host (request-target) v-c-merchant-id", signature="7cr6mZMa1oENhJ5NclGsprmQxwGlo1j3VjqAR6xngxk="'
req<-GET(URL, add_headers(.headers=c('v-c-merchant-id'=merchant, 'v-c-date'=vcdate, 'Host'=ho, 'Signature'=sign)))
content(req)

Here is Cybersource test api where you can verify the data produced.

https://developer.cybersource.com/api/reference/api-reference.html

I am trying to download a report under the reporting tab

Have you tried using `download.file` or whatever other function to download the file now that you have the link? — cory, May 29 '19 at 15:43
It's easier to help you if you include a simple [reproducible example](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) with sample input and desired output that can be used to test and verify possible solutions. Are you sure the response is supposed to be the data? It seems like maybe it's trying to send you a redirect. Can you quote the relevant parts of the API documentation? — MrFlick, May 29 '19 at 15:46
No i havent. i am literrally using the get request to call the api and contenet(request) to read the body mof ythe api. In postman it shows me a a csv data rather than a path. How do i use download.file. Also /space/download_reports/output/dailyreports/reports/2018/10/27/testrest/TRRReport-7931d82d-cf4a-71fa-e053-a2588e0ab27a.csv does not look like a URL path — charles elliott, May 29 '19 at 15:50
That looks like a relative path. I suspect the root is similar to the one you are accessing for the other API calls. As far as using `download.file`, have you tried `?download.file`? — cory, May 29 '19 at 15:55
Not sure how i use ?download.file in the httr GET Request. I have edited my question and posted my code. @MrFlick Yes its supposed to be data. I have tested this in postman. — charles elliott, May 29 '19 at 16:02

score 2 · Accepted Answer · edited May 30 '19 at 08:07

Honestly I'm not exactly sure what's going on here, but I do think I was able to get something to work.

The API seems to like to return data in application/hal+json format which is not one that httr normally requests. You can say you'll accept anything with accept("*") So you can do your request with:

req <- GET(URL, add_headers('v-c-merchant-id'=merchant, 
  'v-c-date'=vcdate, 
  'Host'=ho, 
  'Signature'=sign), accept("*"))

Now we are actually getting the data back that we want, but httr doesn't know how to automatically parse it. So we need to parse it ourselves. This seems to do the trick

readr::read_csv(rawToChar(content(req)), skip=1)

There seems to be a header row which we skip with skip= and then we parse the rest as a CSV file with readr::read_csv.

Why is R HTTR content statement not producing the expected request body?

1 Answers1