webwrite returns error 405, how to find its detailed cause?

I am trying to get certain graphiql working, but am getting 405 error without any detailed error description.

url = 'https://rata.digitraffic.fi/api/v2/graphql/graphiql';
query = '{  currentlyRunningTrains {    trainNumber  }}';
options = weboptions('KeyName','Accept-Encoding','KeyValue','gzip');
res = webwrite(url, query, options);

Is it possible to find what is the exact cause for this HTTP 405 error?

P.S. is there any way to properly add

Accept-Encoding: gzip

field into weboptions?

Answer 1

[Madheswaran]

Hi @Sven Larsen

To access GraphQL data from the server using 'gzip' encoding, please consider the following adjustments to your code:

% Correct the GraphQL endpoint URL
url = 'https://rata.digitraffic.fi/api/v2/graphql/graphql';

% Define the query
query = '{ currentlyRunningTrains { trainNumber }}';

% Set up web options with the necessary headers
options = weboptions;
options.HeaderFields = {'Content-Type', 'application/json'; 'Accept-Encoding', 'gzip'};

% Encode the query in JSON format
queryStruct.query = query;
jsonQuery = jsonencode(queryStruct);

% Send the request and display the response
response = webwrite(url, jsonQuery, options);
disp(response.data);

    currentlyRunningTrains: [114x1 struct]

In this updated version, the URL was corrected to point to the actual GraphQL endpoint instead of the GraphiQL interface. The weboptions were configured to include the necessary headers, specifically 'Content-Type' and 'Accept-Encoding'. Additionally, the query was encoded in JSON format before sending the request.

For more information, refer to the following MathWorks documentation:

1. https://mathworks.com/help/matlab/ref/webwrite.html
2. https://mathworks.com/help/matlab/ref/weboptions.html
3. https://mathworks.com/help/matlab/ref/jsonencode.html

Hope this resolves your issue!