From 99f002baf627f24262e151674aeafa29e0b387d4 Mon Sep 17 00:00:00 2001
From: Eden Tyler-Moss <eden@etylermoss.com>
Date: Tue, 21 Jan 2020 14:03:10 +0000
Subject: [PATCH] feat(gatsby-source-graphql) Execute functions in header.
 (#20731)

* feat(gatsby-source-graphql) Execute functions in headers.

Resolves issue #20690, allowing the use of async functions to define
headers for gatsby-source-graphql. To use, functions can be passed in
the headers object, i.e: headers { authorization: asyncFunc }.

* Changes whole headers parameter to accept async function.

See https://github.com/gatsbyjs/gatsby/pull/20731. Updated README.md to
include new (optional) syntax.
---
 packages/gatsby-source-graphql/README.md          | 6 ++++++
 packages/gatsby-source-graphql/src/gatsby-node.js | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/packages/gatsby-source-graphql/README.md b/packages/gatsby-source-graphql/README.md
index 941597a1ec88d..0993f30e01cd7 100644
--- a/packages/gatsby-source-graphql/README.md
+++ b/packages/gatsby-source-graphql/README.md
@@ -42,6 +42,12 @@ module.exports = {
           // Learn about environment variables: https://gatsby.dev/env-vars
           Authorization: `Bearer ${process.env.GITHUB_TOKEN}`,
         },
+        // HTTP headers alternatively accepts a function (allows async)
+        headers: async () => {
+          return {
+            Authorization: await getAuthorizationToken(),
+          }
+        },
         // Additional options to pass to node-fetch
         fetchOptions: {},
       },
diff --git a/packages/gatsby-source-graphql/src/gatsby-node.js b/packages/gatsby-source-graphql/src/gatsby-node.js
index b1988b7dec867..a02d79a8f42dc 100644
--- a/packages/gatsby-source-graphql/src/gatsby-node.js
+++ b/packages/gatsby-source-graphql/src/gatsby-node.js
@@ -51,8 +51,8 @@ exports.sourceNodes = async (
     link = createHttpLink({
       uri: url,
       fetch,
-      headers,
       fetchOptions,
+      headers: typeof headers === `function` ? await headers() : headers,
     })
   }