1package gock
2
3import (
4	"bytes"
5	"io"
6	"io/ioutil"
7	"net/http"
8	"strconv"
9	"time"
10)
11
12// Responder builds a mock http.Response based on the given Response mock.
13func Responder(req *http.Request, mock *Response, res *http.Response) (*http.Response, error) {
14	// If error present, reply it
15	err := mock.Error
16	if err != nil {
17		return nil, err
18	}
19
20	if res == nil {
21		res = createResponse(req)
22	}
23
24	// Apply response filter
25	for _, filter := range mock.Filters {
26		if !filter(res) {
27			return res, nil
28		}
29	}
30
31	// Define mock status code
32	if mock.StatusCode != 0 {
33		res.Status = strconv.Itoa(mock.StatusCode) + " " + http.StatusText(mock.StatusCode)
34		res.StatusCode = mock.StatusCode
35	}
36
37	// Define headers by merging fields
38	res.Header = mergeHeaders(res, mock)
39
40	// Define mock body, if present
41	if len(mock.BodyBuffer) > 0 {
42		res.ContentLength = int64(len(mock.BodyBuffer))
43		res.Body = createReadCloser(mock.BodyBuffer)
44	}
45
46	// Apply response mappers
47	for _, mapper := range mock.Mappers {
48		if tres := mapper(res); tres != nil {
49			res = tres
50		}
51	}
52
53	// Sleep to simulate delay, if necessary
54	if mock.ResponseDelay > 0 {
55		// allow escaping from sleep due to request context expiration or cancellation
56		t := time.NewTimer(mock.ResponseDelay)
57		select {
58		case <-t.C:
59		case <-req.Context().Done():
60			// cleanly stop the timer
61			if !t.Stop() {
62				<-t.C
63			}
64		}
65	}
66
67	// check if the request context has ended. we could put this up in the delay code above, but putting it here
68	// has the added benefit of working even when there is no delay (very small timeouts, already-done contexts, etc.)
69	if err = req.Context().Err(); err != nil {
70		// cleanly close the response and return the context error
71		io.Copy(ioutil.Discard, res.Body)
72		res.Body.Close()
73		return nil, err
74	}
75
76	return res, err
77}
78
79// createResponse creates a new http.Response with default fields.
80func createResponse(req *http.Request) *http.Response {
81	return &http.Response{
82		ProtoMajor: 1,
83		ProtoMinor: 1,
84		Proto:      "HTTP/1.1",
85		Request:    req,
86		Header:     make(http.Header),
87		Body:       createReadCloser([]byte{}),
88	}
89}
90
91// mergeHeaders copies the mock headers.
92func mergeHeaders(res *http.Response, mres *Response) http.Header {
93	for key, values := range mres.Header {
94		for _, value := range values {
95			res.Header.Add(key, value)
96		}
97	}
98	return res.Header
99}
100
101// createReadCloser creates an io.ReadCloser from a byte slice that is suitable for use as an
102// http response body.
103func createReadCloser(body []byte) io.ReadCloser {
104	return ioutil.NopCloser(bytes.NewReader(body))
105}
106