GET Request problem

[VILANOR]

Hi

I have a GET Request to ask an API
Problem is when I see the GET Results, I’m seeing a question mark in red color in the body column instead of seeing the result of the API
Status column is 200 (so no errors)
Content type is: application/json; charset=utf-8

The API works fine and it returns correct data in JSON format
What else can be wrong?

Thanks

[qqilihq]

@armingrudd Recently posted a solution how such a request could be done with the Palladian nodes. I’d suggest to give it a try. See here:

GET fails if the response does not have Content-Type set

Hi @bedo2991 and welcome to the KNIME forum, This alternative approach will work for you: Pass the URLs to HTTP Retriever and extract the result using HTTP Result Data Extractor and finally the String to JSON node will give you the JSON you are looking for. Here is an example workflow for you: [Untitled] Palladian_Nodes_JSON.knwf (294.8 KB)

Best,
Philipp

[VILANOR]

Hi

I managed to install Palladian and tried to use “HTTP Retriever”, however I’m having an Authentication problem now, status code 401
Using “GET Request” I was able to specify the credentials, but with “HTTP Retriever” there is no setting for credentials. Any workaround ?

Thanks,
Ricard.

[thor]

If you hover over the red question mark a tooltip may appear with further information why the response could not be interpreted correctly. Also the log output may contain more information.

[VILANOR]

This is what KNIME says

[thor]

This looks like the service is sending an empty response.

[VILANOR]

Really? It doesn’t make sense, this is the response I’m getting from the browser:

response.json (92.4 KB)

Is it something wrong in the way I’m making the request?

Thanks

[qqilihq]

however I’m having an Authentication problem now, status code 401
Using “GET Request” I was able to specify the credentials, but with “HTTP Retriever” there is no setting for credentials. Any workaround ?

We do not currently have authentication options in the HTTP Retriever configuration. You could build the Authorization header manually though by using e.g. a Java Snippet node, depending on the authentication method (probably HTTP “Basic”?!?)

– Philipp

PS: Thought I had an example workflow somewhere. I’ll post it in case if I should find it again

PSS: I uploaded the example to my NodePit Space:

HttpRetriever_HttpBasicAuth — NodePit

[thor]

Then there is likely a difference in the two requests. Without having access to that service I cannot tell you more. You can try to extract more response headers such as Content-Length.

[VILANOR]

Authentication method must be NTLM, I don’t know how to adapt the Java Snippet node in order to do that.

[VILANOR]

@thor following your suggestion I added “Content-Length” in the response headers but another red question mark appear:

I ticked the checkbox to extract all the headers and this is the result, in case it helps:

[qqilihq]

Authentication method must be NTLM, I don’t know how to adapt the Java Snippet node in order to do that.

Me neither, never used that.

[thor]

It could be that the chunked Transfer-Encoding is the problem. Is this a public web service that we can use for testing somehow?

[jeffgullick-knime]

WIthin the 4.0.1 version of KNIME AP, we added a new Authentication method NTLM (Labs) which uses a different method for supporting NTLM. Maybe worth a try to see if this helps.