responseplayer_test.go

Documentation: github.com/palantir/go-githubapp/appconfig

     1  // Copyright 2021 Palantir Technologies, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package appconfig
    16  
    17  import (
    18  	"bytes"
    19  	"encoding/base64"
    20  	"fmt"
    21  	"io/ioutil"
    22  	"net/http"
    23  	"strings"
    24  
    25  	"github.com/pkg/errors"
    26  	"gopkg.in/yaml.v2"
    27  )
    28  
    29  type RequestMatcher interface {
    30  	Matches(r *http.Request, body []byte) bool
    31  }
    32  
    33  type ExactPathMatcher string
    34  
    35  func (m ExactPathMatcher) Matches(r *http.Request, body []byte) bool {
    36  	return r.URL.Path == string(m)
    37  }
    38  
    39  type Rule struct {
    40  	Matcher RequestMatcher
    41  	Count   int
    42  
    43  	responses []SavedResponse
    44  	err       error
    45  }
    46  
    47  type ResponsePlayer struct {
    48  	Rules []*Rule
    49  }
    50  
    51  func (rp *ResponsePlayer) AddRule(matcher RequestMatcher, file string) *Rule {
    52  	rule := &Rule{Matcher: matcher}
    53  	rp.Rules = append(rp.Rules, rule)
    54  
    55  	d, err := ioutil.ReadFile(file)
    56  	if err != nil {
    57  		rule.err = errors.Wrapf(err, "failed to read response file: %s", file)
    58  		return rule
    59  	}
    60  
    61  	if err := yaml.Unmarshal(d, &rule.responses); err != nil {
    62  		rule.err = errors.Wrapf(err, "failed to unmarshal response file: %s", file)
    63  		return rule
    64  	}
    65  
    66  	return rule
    67  }
    68  
    69  type SavedResponse struct {
    70  	Status  int               `yaml:"status"`
    71  	Headers map[string]string `yaml:"headers"`
    72  	Body    string            `yaml:"body"`
    73  	Binary  bool
    74  }
    75  
    76  func (r *SavedResponse) Response(req *http.Request) *http.Response {
    77  	header := make(http.Header)
    78  	for k, v := range r.Headers {
    79  		header.Add(k, v)
    80  	}
    81  
    82  	var body []byte
    83  	if r.Binary {
    84  		b, err := base64.StdEncoding.DecodeString(r.Body)
    85  		if err != nil {
    86  			panic("invalid base64 encoded binary body")
    87  		}
    88  		body = b
    89  	} else {
    90  		body = []byte(r.Body)
    91  	}
    92  
    93  	return &http.Response{
    94  		Status:     http.StatusText(r.Status),
    95  		StatusCode: r.Status,
    96  		Proto:      "HTTP/1.1",
    97  		ProtoMajor: 1,
    98  		ProtoMinor: 1,
    99  
   100  		Header:        header,
   101  		Body:          ioutil.NopCloser(bytes.NewReader(body)),
   102  		ContentLength: int64(len(body)),
   103  
   104  		Request: req,
   105  	}
   106  }
   107  
   108  func (rp *ResponsePlayer) findMatch(req *http.Request) *Rule {
   109  	var body []byte
   110  	if req.Body != nil {
   111  		body, _ = ioutil.ReadAll(req.Body)
   112  		_ = req.Body.Close()
   113  	}
   114  
   115  	for _, rule := range rp.Rules {
   116  		if rule.Matcher.Matches(req, body) {
   117  			return rule
   118  		}
   119  	}
   120  	return nil
   121  }
   122  
   123  func (rp *ResponsePlayer) RoundTrip(req *http.Request) (*http.Response, error) {
   124  	rule := rp.findMatch(req)
   125  	if rule == nil {
   126  		return errorResponse(req, http.StatusGone, fmt.Sprintf("no matching rule for \"%s %s\"", req.Method, req.URL.Path))
   127  	}
   128  
   129  	// report any error encountered during loading
   130  	if rule.err != nil {
   131  		return nil, rule.err
   132  	}
   133  
   134  	// fail if there are no responses
   135  	if len(rule.responses) == 0 {
   136  		return errorResponse(req, http.StatusGone, fmt.Sprintf("no responses for \"%s %s\"", req.Method, req.URL.Path))
   137  	}
   138  
   139  	index := rule.Count % len(rule.responses)
   140  	rule.Count++
   141  
   142  	return rule.responses[index].Response(req), nil
   143  }
   144  
   145  func errorResponse(req *http.Request, code int, msg string) (*http.Response, error) {
   146  	body := strings.NewReader(msg)
   147  
   148  	return &http.Response{
   149  		Status:     http.StatusText(code),
   150  		StatusCode: code,
   151  		Proto:      "HTTP/1.1",
   152  		ProtoMajor: 1,
   153  		ProtoMinor: 1,
   154  
   155  		Header:        make(http.Header),
   156  		Body:          ioutil.NopCloser(body),
   157  		ContentLength: body.Size(),
   158  
   159  		Request: req,
   160  	}, nil
   161  }
   162
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