feat: export headers to reduce duplication (#33)

googleapis · Feb 16, 2018 · 0b6eb38 · 0b6eb38
1 parent 5105200
commit 0b6eb38
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Showing 2 changed files with 11 additions and 8 deletions.
diff --git a/src/index.ts b/src/index.ts
@@ -6,6 +6,8 @@ export const HOST_ADDRESS = 'http://metadata.google.internal';
 export const BASE_PATH = '/computeMetadata/v1';
 export const BASE_URL = HOST_ADDRESS + BASE_PATH;
 export const HEADER_NAME = 'Metadata-Flavor';
+export const HEADER_VALUE = 'Google';
+export const HEADERS = Object.freeze({[HEADER_NAME]: HEADER_VALUE});
 
 export type Options = AxiosRequestConfig&
     {[index: string]: {} | string | undefined, property?: string, uri?: string};
@@ -43,15 +45,15 @@ async function metadataAccessor(type: string, options?: string|Options) {
   rax.attach(ax);
   const baseOpts = {
     url: `${BASE_URL}/${type}${property}`,
-    headers: {'Metadata-Flavor': 'Google'},
+    headers: Object.assign({}, HEADERS),
     raxConfig: {noResponseRetries: 0}
   };
   const reqOpts = extend(true, baseOpts, options);
   delete (reqOpts as {property: string}).property;
   return ax.request(reqOpts)
       .then(res => {
         // NOTE: node.js converts all incoming headers to lower case.
-        if (res.headers[HEADER_NAME.toLowerCase()] !== 'Google') {
+        if (res.headers[HEADER_NAME.toLowerCase()] !== HEADER_VALUE) {
           throw new Error(`Invalid response from metadata service: incorrect ${
               HEADER_NAME} header.`);
         } else if (!res.data) {

diff --git a/test/index.test.ts b/test/index.test.ts
@@ -12,7 +12,7 @@ const PROPERTY = 'property';
 
 // NOTE: nodejs switches all incoming header names to lower case.
 const HEADERS = {
-  'metadata-flavor': 'Google'
+  [gcp.HEADER_NAME.toLowerCase()]: gcp.HEADER_VALUE
 };
 
 nock.disableNetConnect();
@@ -31,8 +31,8 @@ test.serial('should access all the metadata properly', async t => {
   const res = await gcp.instance();
   scope.done();
   t.is(res.config.url, `${BASE_URL}/${TYPE}`);
-  t.is(res.config.headers[HEADER_NAME], 'Google');
-  t.is(res.headers[HEADER_NAME.toLowerCase()], 'Google');
+  t.is(res.config.headers[HEADER_NAME], gcp.HEADER_VALUE);
+  t.is(res.headers[HEADER_NAME.toLowerCase()], gcp.HEADER_VALUE);
 });
 
 test.serial('should access a specific metadata property', async t => {
@@ -82,9 +82,10 @@ test.serial('should return error when res is empty', async t => {
 });
 
 test.serial('should return error when flavor header is incorrect', async t => {
-  const scope = nock(HOST).get(`${PATH}/${TYPE}`).reply(200, {}, {
-    'metadata-flavor': 'Hazelnut'
-  });
+  const scope =
+      nock(HOST)
+          .get(`${PATH}/${TYPE}`)
+          .reply(200, {}, {[gcp.HEADER_NAME.toLowerCase()]: 'Hazelnut'});
   await t.throws(
       gcp.instance(),
       `Invalid response from metadata service: incorrect Metadata-Flavor header.`);