~emersion/gqlclient

gqlclient/client.go -rw-r--r-- 3.6 KiB
4e6e9c76Simon Ser Check response Content-Type 5 months ago
                                                                                
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
package gqlclient

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"mime"
	"net/http"
)

// Client is a GraphQL HTTP client.
type Client struct {
	endpoint string
	http     *http.Client
}

// New creates a new GraphQL client with the specified endpoint.
//
// If hc is nil, http.DefaultClient is used.
func New(endpoint string, hc *http.Client) *Client {
	if hc == nil {
		hc = http.DefaultClient
	}
	return &Client{
		endpoint: endpoint,
		http:     hc,
	}
}

// Operation describes a GraphQL operation.
//
// An operation is a query with variables.
type Operation struct {
	query   string
	vars    map[string]interface{}
	uploads map[string]Upload
}

// NewOperation creates a new GraphQL operation.
func NewOperation(query string) *Operation {
	return &Operation{query: query}
}

// Var defines a new variable.
//
// If the variable is already defined, Var panics.
func (op *Operation) Var(k string, v interface{}) {
	if op.vars == nil {
		op.vars = make(map[string]interface{})
		op.uploads = make(map[string]Upload)
	}
	if _, ok := op.vars[k]; ok {
		panic(fmt.Sprintf("gqlclient: called Operation.Var twice on %q", k))
	}
	op.vars[k] = v

	// TODO: support more deeply nested uploads
	switch v := v.(type) {
	case Upload:
		op.uploads[k] = v
	case *Upload:
		if v != nil {
			op.uploads[k] = *v
		}
	case []Upload:
		for i, upload := range v {
			upload := upload // copy
			op.uploads[fmt.Sprintf("%v.%v", k, i)] = upload
		}
	case []*Upload:
		for i, upload := range v {
			if upload != nil {
				op.uploads[fmt.Sprintf("%v.%v", k, i)] = *upload
			}
		}
	}
}

// Execute sends the operation to the GraphQL server.
//
// The data returned by the server will be decoded into the data argument.
func (c *Client) Execute(ctx context.Context, op *Operation, data interface{}) error {
	reqData := struct {
		Query string                 `json:"query"`
		Vars  map[string]interface{} `json:"variables"`
	}{
		Query: op.query,
		Vars:  op.vars,
	}

	var reqBuf bytes.Buffer
	if err := json.NewEncoder(&reqBuf).Encode(&reqData); err != nil {
		return fmt.Errorf("failed to encode request payload: %v", err)
	}

	var reqBody io.Reader
	var contentType string
	if len(op.uploads) > 0 {
		pr, pw := io.Pipe()
		defer pr.Close()

		reqBody = pr
		contentType = writeMultipart(pw, op.uploads, &reqBuf)
	} else {
		reqBody = &reqBuf
		contentType = "application/json; charset=utf-8"
	}

	// io.TeeReader(reqBody, os.Stderr)
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.endpoint, reqBody)
	if err != nil {
		return fmt.Errorf("failed to create HTTP request: %v", err)
	}
	req.Header.Set("Content-Type", contentType)
	req.Header.Set("Accept", "application/json")

	resp, err := c.http.Do(req)
	if err != nil {
		return fmt.Errorf("HTTP request failed: %v", err)
	}
	defer resp.Body.Close()

	contentType = resp.Header.Get("Content-Type")
	if contentType == "" {
		contentType = "text/plain"
	}
	mediaType, _, err := mime.ParseMediaType(contentType)
	if err != nil {
		return fmt.Errorf("invalid Content-Type %q: %v", contentType, err)
	} else if mediaType != "application/json" {
		if resp.StatusCode/100 != 2 {
			return fmt.Errorf("HTTP server error: %v %v", resp.StatusCode, resp.Status)
		}
		return fmt.Errorf("invalid Content-Type %q: expected application/json", contentType)
	}

	respData := struct {
		Data   interface{}
		Errors []Error
	}{Data: data}
	// io.TeeReader(resp.Body, os.Stderr)
	if err := json.NewDecoder(resp.Body).Decode(&respData); err != nil {
		return fmt.Errorf("failed to decode response payload: %v", err)
	}

	if len(respData.Errors) > 0 {
		return &respData.Errors[0]
	}
	return nil
}