private static async Task <GraphQlParameters> GetParametersAsync(HttpRequest request)
{
// http://graphql.org/learn/serving-over-http/#http-methods-headers-and-body
string body = null;
if (request.Method == "POST")
{
// Read request body
using (var sr = new StreamReader(request.Body))
{
body = await sr.ReadToEndAsync();
}
}
MediaTypeHeaderValue.TryParse(request.ContentType, out MediaTypeHeaderValue contentType);
GraphQlParameters parameters;
switch (contentType.MediaType)
{
case "application/json":
// Parse request as json
parameters = JsonConvert.DeserializeObject <GraphQlParameters>(body);
break;
case "application/graphql":
// The whole body is the query
parameters = new GraphQlParameters {
Query = body
};
break;
default:
// Don't parse anything
parameters = new GraphQlParameters();
break;
}
string query = request.Query["query"];
// Query string "query" overrides a query in the body
parameters.Query = query ?? parameters.Query;
return(parameters);
}
public async Task Invoke(HttpContext httpContext)
{
var sent = false;
if (httpContext.Request.Path.StartsWithSegments("/graphql"))
{
var request = httpContext.Request;
var response = httpContext.Response;
// GraphQL HTTP only supports GET and POST methods.
if (request.Method != "GET" && request.Method != "POST")
{
response.Headers.Add("Allow", "GET, POST");
response.StatusCode = 405;
return;
}
GraphQlParameters parameters = await GetParametersAsync(request);
var schema = new Schema {
Query = new BookQuery(_bookRepository)
};
var result = await new DocumentExecuter().ExecuteAsync(options =>
{
options.Schema = schema;
options.Query = parameters.Query;
options.OperationName = parameters.OperationName;
options.Inputs = parameters.GetInputs();
});
CheckForErrors(result);
await WriteResult(httpContext, result);
sent = true;
}
if (!sent)
{
await _next(httpContext);
}
}
