1// Copyright 2015 go-swagger maintainers
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
15package runtime
16
17import (
18	"bytes"
19	"encoding"
20	"errors"
21	"fmt"
22	"io"
23	"reflect"
24
25	"github.com/go-openapi/swag"
26)
27
28func defaultCloser() error { return nil }
29
30type byteStreamOpt func(opts *byteStreamOpts)
31
32// ClosesStream when the bytestream consumer or producer is finished
33func ClosesStream(opts *byteStreamOpts) {
34	opts.Close = true
35}
36
37type byteStreamOpts struct {
38	Close bool
39}
40
41// ByteStreamConsumer creates a consmer for byte streams,
42// takes a Writer/BinaryUnmarshaler interface or binary slice by reference,
43// and reads from the provided reader
44func ByteStreamConsumer(opts ...byteStreamOpt) Consumer {
45	var vals byteStreamOpts
46	for _, opt := range opts {
47		opt(&vals)
48	}
49
50	return ConsumerFunc(func(reader io.Reader, data interface{}) error {
51		if reader == nil {
52			return errors.New("ByteStreamConsumer requires a reader") // early exit
53		}
54
55		close := defaultCloser
56		if vals.Close {
57			if cl, ok := reader.(io.Closer); ok {
58				close = cl.Close
59			}
60		}
61		defer close()
62
63		if wrtr, ok := data.(io.Writer); ok {
64			_, err := io.Copy(wrtr, reader)
65			return err
66		}
67
68		buf := new(bytes.Buffer)
69		_, err := buf.ReadFrom(reader)
70		if err != nil {
71			return err
72		}
73		b := buf.Bytes()
74
75		if bu, ok := data.(encoding.BinaryUnmarshaler); ok {
76			return bu.UnmarshalBinary(b)
77		}
78
79		if t := reflect.TypeOf(data); data != nil && t.Kind() == reflect.Ptr {
80			v := reflect.Indirect(reflect.ValueOf(data))
81			if t = v.Type(); t.Kind() == reflect.Slice && t.Elem().Kind() == reflect.Uint8 {
82				v.SetBytes(b)
83				return nil
84			}
85		}
86
87		return fmt.Errorf("%v (%T) is not supported by the ByteStreamConsumer, %s",
88			data, data, "can be resolved by supporting Writer/BinaryUnmarshaler interface")
89	})
90}
91
92// ByteStreamProducer creates a producer for byte streams,
93// takes a Reader/BinaryMarshaler interface or binary slice,
94// and writes to a writer (essentially a pipe)
95func ByteStreamProducer(opts ...byteStreamOpt) Producer {
96	var vals byteStreamOpts
97	for _, opt := range opts {
98		opt(&vals)
99	}
100	return ProducerFunc(func(writer io.Writer, data interface{}) error {
101		if writer == nil {
102			return errors.New("ByteStreamProducer requires a writer") // early exit
103		}
104		close := defaultCloser
105		if vals.Close {
106			if cl, ok := writer.(io.Closer); ok {
107				close = cl.Close
108			}
109		}
110		defer close()
111
112		if rc, ok := data.(io.ReadCloser); ok {
113			defer rc.Close()
114		}
115
116		if rdr, ok := data.(io.Reader); ok {
117			_, err := io.Copy(writer, rdr)
118			return err
119		}
120
121		if bm, ok := data.(encoding.BinaryMarshaler); ok {
122			bytes, err := bm.MarshalBinary()
123			if err != nil {
124				return err
125			}
126
127			_, err = writer.Write(bytes)
128			return err
129		}
130
131		if data != nil {
132			if e, ok := data.(error); ok {
133				_, err := writer.Write([]byte(e.Error()))
134				return err
135			}
136
137			v := reflect.Indirect(reflect.ValueOf(data))
138			if t := v.Type(); t.Kind() == reflect.Slice && t.Elem().Kind() == reflect.Uint8 {
139				_, err := writer.Write(v.Bytes())
140				return err
141			}
142			if t := v.Type(); t.Kind() == reflect.Struct || t.Kind() == reflect.Slice {
143				b, err := swag.WriteJSON(data)
144				if err != nil {
145					return err
146				}
147				_, err = writer.Write(b)
148				return err
149			}
150		}
151
152		return fmt.Errorf("%v (%T) is not supported by the ByteStreamProducer, %s",
153			data, data, "can be resolved by supporting Reader/BinaryMarshaler interface")
154	})
155}
156