fix: Correctly handle array header values

docs/server/request.md

@@ -6,10 +6,10 @@
 
 Get a header with a given name.
 
-| Param       | Type     | Description            |
-| ----------- | -------- | ---------------------- |
-| name        | `String` | The name of the header |
-| **Returns** | `String` | The header value       |
+| Param       | Type             | Description            |
+| ----------- | ---------------- | ---------------------- |
+| name        | `String`         | The name of the header |
+| **Returns** | `String | Array` | The header value       |
 
 **Example**
 
@@ -25,7 +25,7 @@ removed.
 | Param       | Type                      | Description              |
 | ----------- | ------------------------- | ------------------------ |
 | name        | `String`                  | The name of the header   |
-| value       | `String`                  | The value for the header |
+| value       | `String | Array`          | The value for the header |
 | **Returns** | [Request](server/request) | The current request      |
 
 **Example**
@@ -48,6 +48,7 @@ removed.
 
 ```js
 req.setHeaders({
+  Accept: ['text/html', 'image/*'],
   'Content-Type': 'application/json',
   'Content-Length': 42
 });

docs/server/response.md

@@ -44,10 +44,10 @@ res.status(200);
 
 Get a header with a given name.
 
-| Param       | Type     | Description            |
-| ----------- | -------- | ---------------------- |
-| name        | `String` | The name of the header |
-| **Returns** | `String` | The header value       |
+| Param       | Type             | Description            |
+| ----------- | ---------------- | ---------------------- |
+| name        | `String`         | The name of the header |
+| **Returns** | `String | Array` | The header value       |
 
 **Example**
 
@@ -63,7 +63,7 @@ removed.
 | Param       | Type                        | Description              |
 | ----------- | --------------------------- | ------------------------ |
 | name        | `String`                    | The name of the header   |
-| value       | `String`                    | The value for the header |
+| value       | `String | Array`            | The value for the header |
 | **Returns** | [Response](server/response) | The current response     |
 
 **Example**
@@ -86,6 +86,7 @@ removed.
 
 ```js
 res.setHeaders({
+  Accept: ['text/html', 'image/*'],
   'Content-Type': 'application/json',
   'Content-Length': 42
 });

packages/@pollyjs/adapter/src/index.js

@@ -3,6 +3,7 @@ import { ACTIONS, MODES, Serializers, assert } from '@pollyjs/utils';
 import Interceptor from './-private/interceptor';
 import isExpired from './utils/is-expired';
 import stringifyRequest from './utils/stringify-request';
+import normalizeRecordedResponse from './utils/normalize-recorded-response';
 
 const REQUEST_HANDLER = Symbol();
 
@@ -185,19 +186,11 @@ export default class Adapter {
       await this.timeout(pollyRequest, recordingEntry);
       pollyRequest.action = ACTIONS.REPLAY;
 
-      const { status, statusText, headers, content } = recordingEntry.response;
-      const normalizedResponse = {
-        statusText,
-        statusCode: status,
-        headers: (headers || []).reduce((accum, { name, value }) => {
-          accum[name] = value;
-
-          return accum;
-        }, {}),
-        body: content && content.text
-      };
-
-      return this.onReplay(pollyRequest, normalizedResponse, recordingEntry);
+      return this.onReplay(
+        pollyRequest,
+        normalizeRecordedResponse(recordingEntry.response),
+        recordingEntry
+      );
     }
 
     if (config.recordIfMissing) {

packages/@pollyjs/adapter/src/utils/normalize-recorded-response.js

@@ -0,0 +1,30 @@
+const { isArray } = Array;
+
+export default function normalizeRecordedResponse(response) {
+  const { status, statusText, headers, content } = response;
+
+  return {
+    statusText,
+    statusCode: status,
+    headers: normalizeHeaders(headers),
+    body: content && content.text
+  };
+}
+
+function normalizeHeaders(headers) {
+  return (headers || []).reduce((accum, { name, value, _fromType }) => {
+    const existingValue = accum[name];
+
+    if (existingValue) {
+      if (!isArray(existingValue)) {
+        accum[name] = [existingValue];
+      }
+
+      accum[name].push(value);
+    } else {
+      accum[name] = _fromType === 'array' ? [value] : value;
+    }
+
+    return accum;
+  }, {});
+}

packages/@pollyjs/persister/src/har/request.js

@@ -2,6 +2,7 @@ import getByteLength from 'utf8-byte-length';
 import setCookies from 'set-cookie-parser';
 
 import toNVPairs from './utils/to-nv-pairs';
+import getFirstHeader from './utils/get-first-header';
 
 function headersSize(request) {
   const keys = [];
@@ -34,7 +35,7 @@ export default class Request {
 
     if (request.body) {
       this.postData = {
-        mimeType: request.getHeader('Content-Type') || 'text/plain',
+        mimeType: getFirstHeader(request, 'Content-Type') || 'text/plain',
         params: []
       };
 
@@ -43,8 +44,10 @@ export default class Request {
       }
     }
 
-    if (request.hasHeader('Content-Length')) {
-      this.bodySize = parseInt(request.getHeader('Content-Length'), 10);
+    const contentLength = getFirstHeader(request, 'Content-Length');
+
+    if (contentLength) {
+      this.bodySize = parseInt(contentLength, 10);
     } else {
       this.bodySize =
         this.postData && this.postData.text

packages/@pollyjs/persister/src/har/response.js

@@ -2,6 +2,7 @@ import getByteLength from 'utf8-byte-length';
 import setCookies from 'set-cookie-parser';
 
 import toNVPairs from './utils/to-nv-pairs';
+import getFirstHeader from './utils/get-first-header';
 
 function headersSize(response) {
   const keys = [];
@@ -28,24 +29,26 @@ export default class Response {
     this.headers = toNVPairs(response.headers);
     this.headersSize = headersSize(this);
     this.cookies = setCookies.parse(response.getHeader('Set-Cookie'));
-    this.redirectURL = '';
+    this.redirectURL = getFirstHeader(response, 'Location') || '';
 
     this.content = {
-      mimeType: response.getHeader('Content-Type') || 'text/plain'
+      mimeType: getFirstHeader(response, 'Content-Type') || 'text/plain'
     };
 
     if (response.body && typeof response.body === 'string') {
       this.content.text = response.body;
     }
 
-    if (response.hasHeader('Content-Length')) {
-      this.content.size = parseInt(response.getHeader('Content-Length'), 10);
+    const contentLength = getFirstHeader(response, 'Content-Length');
+
+    if (contentLength) {
+      this.content.size = parseInt(contentLength, 10);
     } else {
       this.content.size = this.content.text
         ? getByteLength(this.content.text)
         : 0;
     }
 
-    this.bodySize = this.content ? this.content.size : 0;
+    this.bodySize = this.content.size;
   }
 }

packages/@pollyjs/persister/src/har/utils/get-first-header.js

@@ -0,0 +1,20 @@
+const { isArray } = Array;
+
+/**
+ * Get the value of the given header name. If the value is an array,
+ * get the first value.
+ *
+ * @export
+ * @param {PollyRequest | PollyResponse} r
+ * @param {string} name
+ * @returns {string | undefined}
+ */
+export default function getFirstHeader(r, name) {
+  const value = r.getHeader(name);
+
+  if (isArray(value)) {
+    return value.length > 0 ? value[0] : '';
+  }
+
+  return value;
+}

packages/@pollyjs/persister/src/har/utils/to-nv-pairs.js

@@ -1,5 +1,21 @@
 const { keys } = Object;
+const { isArray } = Array;
 
 export default function toNVPairs(o) {
-  return keys(o || {}).map(name => ({ name, value: o[name] }));
+  return keys(o || {}).reduce((pairs, name) => {
+    const value = o[name];
+
+    if (isArray(value)) {
+      // _fromType is used to convert the stored header back into the
+      // type it originally was. Take the following example:
+      //   { 'content-type': ['text/htm'] }
+      //     => { name: 'content-type', value: 'text/html', _fromType: 'array }
+      //     => { 'content-type': ['text/htm'] }
+      pairs.push(...value.map(v => ({ name, value: v, _fromType: 'array' })));
+    } else {
+      pairs.push({ name, value });
+    }
+
+    return pairs;
+  }, []);
 }

tests/integration/persister-tests.js

@@ -129,6 +129,70 @@ export default function persisterTests() {
     this.polly.recordingName = recordingName;
   });
 
+  it('should correctly handle array header values', async function() {
+    const { recordingId, server, persister } = this.polly;
+    let responseCalled = false;
+
+    this.polly.record();
+
+    server
+      .get(this.recordUrl())
+      .configure({ matchRequestsBy: { order: false } })
+      .once('beforeResponse', (req, res) => {
+        res.setHeaders({
+          string: 'foo',
+          one: ['foo'],
+          two: ['foo', 'bar']
+        });
+      });
+
+    await this.fetchRecord();
+    await persister.persist();
+
+    const har = await persister.find(recordingId);
+    const { headers } = har.log.entries[0].response;
+
+    expect(await validate.har(har)).to.be.true;
+    expect(
+      headers.filter(({ _fromType }) => _fromType === 'array')
+    ).to.have.lengthOf(3);
+
+    this.polly.replay();
+
+    server.get(this.recordUrl()).once('response', (req, res) => {
+      expect(res.getHeader('string')).to.equal('foo');
+      expect(res.getHeader('one')).to.deep.equal(['foo']);
+      expect(res.getHeader('two')).to.deep.equal(['foo', 'bar']);
+      responseCalled = true;
+    });
+
+    await this.fetchRecord();
+    expect(responseCalled).to.be.true;
+  });
+
+  it('should correctly handle array header values where a single header is expected', async function() {
+    const { recordingId, server, persister } = this.polly;
+
+    this.polly.record();
+
+    server.get(this.recordUrl()).once('beforeResponse', (req, res) => {
+      res.setHeaders({
+        Location: ['./index.html'],
+        'Content-Type': ['application/json']
+      });
+    });
+
+    await this.fetchRecord();
+    await persister.persist();
+
+    const har = await persister.find(recordingId);
+    const { content, redirectURL } = har.log.entries[0].response;
+
+    expect(await validate.har(har)).to.be.true;
+    expect(content.mimeType).to.equal('application/json');
+    expect(redirectURL).to.equal('./index.html');
+  });
+
   it('should error when persisting a failed request', async function() {
     let error;