fix: introspection error

README.md

@@ -105,15 +105,29 @@ cd swift-graphql
 make install
 ```
 
-To run the generator type `swift-graphql`. If you are using any custom scalars, you should create a configuration file called `swiftgraphql.yml` and put in data-type mappings as a key-value dictionary like this. Keys should be GraphQL types, and values should be SwiftGraphQL Codecs.
+### Generating the code
+
+```
+USAGE: swift-graphql <endpoint> [--config <config>] [--output <output>]
+
+ARGUMENTS:
+  <endpoint>              GraphQL server endpoint.
+
+OPTIONS:
+  --config <config>       Relative path from CWD to your YML config file.
+  -o, --output <output>   Relative path from CWD to the output file.
+  -h, --help              Show help information.
+```
+
+To run the generator, type `swift-graphql`. If you are using any custom scalars, you should create a configuration file called `swiftgraphql.yml` and put in data-type mappings as a key-value dictionary like this. Keys should be GraphQL types, and values should be SwiftGraphQL Codecs.
 
 ```yml
 scalars:
   Date: DateTime
   Upload: Upload
 ```
 
-You can also run `swift-graphql help` to learn more about options and how it works.
+You can also run `swift-graphql --help` to learn more about options and how it works.
 
 ---
 

Sources/GraphQLAST/Introspection.swift

@@ -153,13 +153,17 @@ func fetch(from endpoint: URL, withHeaders headers: [String: String] = [:]) thro
     }
 
     request.setValue("application/json", forHTTPHeaderField: "Content-Type")
-    request.setValue("application/json", forHTTPHeaderField: "Accept")
+    request.setValue("*/*", forHTTPHeaderField: "Accept")
     request.httpMethod = "POST"
 
-    let query: [String: Any] = ["query": introspectionQuery]
+    let payload: [String: Any] = [
+        "query": introspectionQuery,
+        "variables": [String: Any](),
+        "operationName": "IntrospectionQuery"
+    ]
 
     request.httpBody = try! JSONSerialization.data(
-        withJSONObject: query,
+        withJSONObject: payload,
         options: JSONSerialization.WritingOptions()
     )
 
@@ -176,8 +180,14 @@ func fetch(from endpoint: URL, withHeaders headers: [String: String] = [:]) thro
             return
         }
 
-        guard let httpResponse = response as? HTTPURLResponse, (200 ... 299).contains(httpResponse.statusCode) else {
-            result = .failure(.statusCode)
+        guard let httpResponse = response as? HTTPURLResponse else {
+            result = .failure(.unknown)
+            semaphore.signal()
+            return
+        }
+
+        guard (200 ... 299).contains(httpResponse.statusCode) else {
+            result = .failure(.statusCode(httpResponse.statusCode))
             semaphore.signal()
             return
         }
@@ -205,7 +215,7 @@ func fetch(from endpoint: URL, withHeaders headers: [String: String] = [:]) thro
 
 enum IntrospectionError: Error {
     case error(Error)
-    case statusCode
+    case statusCode(Int)
     case unknown
 }
 

Sources/SwiftGraphQLCLI/main.swift

@@ -22,6 +22,12 @@ struct SwiftGraphQLCLI: ParsableCommand {
 
     @Option(help: "Include this Authorization header in the request to the endpoint.")
     var authorization: String?
+
+    // MARK: - Configuration
+
+    var configuration = CommandConfiguration(
+        commandName: "swift-graphql"
+    )
 
     // MARK: - Main
 

Tests/GraphQLASTTests/ASTIntrospectionTests.swift

@@ -0,0 +1,15 @@
+@testable import GraphQLAST
+import XCTest
+
+final class ASTIntrospectionTests: XCTestCase {
+    /* Schema */
+
+    func testIntrospectServer() throws {
+        let url = URL(string: "https://swapi-ql.herokuapp.com/graphql")!
+        let schema = try Schema(from: url)
+
+        /* Tests */
+
+        XCTAssertNotNil(schema)
+    }
+}