public async Task Invoke(HttpContext httpContext)
{
var logger = httpContext.RequestServices.GetService <ILogger <GraphQlMiddleware> >();
HttpRequest request = httpContext.Request;
HttpResponse 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;
}
// Check authorization
if (options.AuthorizationPolicy != null)
{
var authorizationService = httpContext.RequestServices.GetRequiredService <IAuthorizationService>();
var authzResult = await authorizationService.AuthorizeAsync(httpContext.User, options.AuthorizationPolicy);
if (!authzResult.Succeeded)
{
await httpContext.ForbidAsync();
return;
}
}
GraphQlParameters parameters = await GetParametersAsync(request);
ISchema schema = schemaProvider.Create(httpContext.RequestServices);
var result = await executer.ExecuteAsync(executionOptions =>
{
executionOptions.Schema = schema;
executionOptions.Query = parameters.Query;
executionOptions.OperationName = parameters.OperationName;
executionOptions.Inputs = parameters.GetInputs();
executionOptions.CancellationToken = httpContext.RequestAborted;
executionOptions.ComplexityConfiguration = options.ComplexityConfiguration;
executionOptions.UserContext = httpContext;
executionOptions.ExposeExceptions = options.ExposeExceptions;
ConfigureDocumentExecutionListeners(executionOptions, executionListeners);
});
if (result.Errors?.Count > 0)
{
logger.LogError("GraphQL Result {Errors}", result.Errors);
}
var writer = new DocumentWriter(indent: options.FormatOutput);
var json = writer.Write(result);
response.StatusCode = 200;
response.ContentType = "application/json; charset=utf-8";
await response.WriteAsync(json);
}
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);
}
