Add Python document extractor to language server

Python does not have tagged templates but it's safe to assume that the user
will use a function named `gql()` to wrap document literals in code.

Author: patrys

packages/apollo-language-server/src/document.ts

@@ -63,20 +63,22 @@ export function extractGraphQLDocuments(
     case "javascriptreact":
     case "typescript":
     case "typescriptreact":
-      return extractGraphQLDocumentsFromTemplateLiterals(document);
+      return extractGraphQLDocumentsFromJSTemplateLiterals(document);
+    case "python":
+      return extractGraphQLDocumentsFromPythonStrings(document);
     default:
       return null;
   }
 }
 
-function extractGraphQLDocumentsFromTemplateLiterals(
+function extractGraphQLDocumentsFromJSTemplateLiterals(
   document: TextDocument
 ): GraphQLDocument[] | null {
   const text = document.getText();
 
   const documents: GraphQLDocument[] = [];
 
-  const regExp = new RegExp("gql" + "\\s*`([\\s\\S]+?)`", "mg");
+  const regExp = /gql\s*`([\s\S]+?)`/gm;
 
   let result;
   while ((result = regExp.exec(text)) !== null) {
@@ -95,6 +97,38 @@ function extractGraphQLDocumentsFromTemplateLiterals(
   return documents;
 }
 
+function extractGraphQLDocumentsFromPythonStrings(
+  document: TextDocument
+): GraphQLDocument[] | null {
+  const text = document.getText();
+
+  const documents: GraphQLDocument[] = [];
+
+  const regExp = /\b(gql\s*\(\s*[bfru]*("(?:"")?|'(?:'')?))([\s\S]+?)\2\s*\)/gm;
+
+  let result;
+  while ((result = regExp.exec(text)) !== null) {
+    const contents = replacePlaceholdersWithWhiteSpace(result[3]);
+    const position = document.positionAt(result.index + result[1].length);
+    const locationOffset: SourceLocation = {
+      line: position.line + 1,
+      column: position.character + 1
+    };
+    console.log(
+      result.index,
+      result.index + result[1].length,
+      position,
+      locationOffset
+    );
+    const source = new Source(contents, document.uri, locationOffset);
+    documents.push(new GraphQLDocument(source));
+  }
+
+  if (documents.length < 1) return null;
+
+  return documents;
+}
+
 function replacePlaceholdersWithWhiteSpace(content: string) {
   return content.replace(/\$\{(.+)?\}/g, match => {
     return Array(match.length).join(" ");

packages/apollo-language-server/src/project/base.ts

@@ -37,7 +37,8 @@ const fileAssociations: { [extension: string]: string } = {
   ".js": "javascript",
   ".ts": "typescript",
   ".jsx": "javascriptreact",
-  ".tsx": "typescriptreact"
+  ".tsx": "typescriptreact",
+  ".py": "python"
 };
 
 export interface GraphQLProjectConfig {