Add fromHttp2Headers

src/metadata.ts

@@ -179,4 +179,33 @@ export class Metadata {
     });
     return result;
   }
+
+  /**
+   * Returns a new Metadata object based fields in a given IncomingHttpHeaders
+   * object.
+   * @param headers An IncomingHttpHeaders object.
+   */
+  static fromHttp2Headers(headers: http2.IncomingHttpHeaders): Metadata {
+    const result = new Metadata();
+    forOwn(headers, (values, key) => {
+      if (isBinaryKey(key)) {
+        if (Array.isArray(values)) {
+          values.forEach((value) => {
+            result.add(key, Buffer.from(value, 'base64'));
+          })
+        } else {
+          result.add(key, Buffer.from(values, 'base64'));
+        }
+      } else {
+        if (Array.isArray(values)) {
+          values.forEach((value) => {
+            result.add(key, value);
+          })
+        } else {
+          result.add(key, values);
+        }
+      }
+    });
+    return result;
+  }
 }

test/test-metadata.ts

@@ -1,4 +1,5 @@
 import * as assert from 'assert';
+import * as http2 from 'http2';
 import { range } from 'lodash';
 import * as metadata from '../src/metadata';
 
@@ -6,6 +7,13 @@ class Metadata extends metadata.Metadata {
   getInternalRepresentation() {
     return this.internalRepr;
   }
+
+  static fromHttp2Headers(headers: http2.IncomingHttpHeaders): Metadata {
+    const result = metadata.Metadata.fromHttp2Headers(headers) as Metadata;
+    result.getInternalRepresentation =
+      Metadata.prototype.getInternalRepresentation;
+    return result;
+  }
 }
 
 const validKeyChars = '0123456789abcdefghijklmnopqrstuvwxyz_-.';
@@ -224,7 +232,7 @@ describe('Metadata', () => {
   });
 
   describe('toHttp2Headers', () => {
-    it('creates an http2.OutgoingHttpHeaders object', () => {
+    it('creates an OutgoingHttpHeaders object with expected values', () => {
       metadata.add('key1', 'value1');
       metadata.add('Key2', 'value2');
       metadata.add('KEY3', 'value3a');
@@ -249,4 +257,37 @@ describe('Metadata', () => {
       assert.deepEqual(metadata.toHttp2Headers(), {});
     });
   });
+
+  describe('fromHttp2Headers', () => {
+    it('creates a Metadata object with expected values', () => {
+      const headers = {
+        key1: 'value1',
+        key2: ['value2'],
+        key3: ['value3a', 'value3b'],
+        'key-bin': [
+          'AAECAwQFBgcICQoLDA0ODw==',
+          'EBESExQVFhcYGRobHB0eHw==',
+          'AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh8='
+        ]
+      };
+      const metadataFromHeaders = Metadata.fromHttp2Headers(headers);
+      const internalRepr = metadataFromHeaders.getInternalRepresentation();
+      assert.deepEqual(internalRepr, {
+        key1: ['value1'],
+        key2: ['value2'],
+        key3: ['value3a', 'value3b'],
+        'key-bin': [
+          Buffer.from(range(0, 16)),
+          Buffer.from(range(16, 32)),
+          Buffer.from(range(0, 32))
+        ]
+      });
+    });
+
+    it('creates an empty Metadata object from empty headers', () => {
+      const metadataFromHeaders = Metadata.fromHttp2Headers({});
+      const internalRepr = metadataFromHeaders.getInternalRepresentation();
+      assert.deepEqual(internalRepr, {});
+    });
+  });
 });