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
|
function getContentType(headers) {
if(!headers) {
return;
}
for(let key in headers) {
if(key.toLowerCase() === "content-type") {
return headers[key];
}
}
}
// Inspired by `resp-modifier` https://github.com/shakyShane/resp-modifier/blob/4a000203c9db630bcfc3b6bb8ea2abc090ae0139/index.js
function wrapResponse(resp, transformHtml) {
resp._wrappedOriginalWrite = resp.write;
resp._wrappedOriginalWriteHead = resp.writeHead;
resp._wrappedOriginalEnd = resp.end;
resp._wrappedHeaders = [];
resp._wrappedTransformHtml = transformHtml;
resp._hasEnded = false;
resp._shouldForceEnd = false;
// Compatibility with web standards Response()
Object.defineProperty(resp, "body", {
// Returns write cache
get: function() {
if(typeof this._writeCache === "string") {
return this._writeCache;
}
},
// Usage:
// res.body = ""; // overwrite existing content
// res.body += ""; // append to existing content, can also res.write("") to append
set: function(data) {
if(typeof data === "string") {
this._writeCache = data;
}
}
});
// Compatibility with web standards Response()
Object.defineProperty(resp, "bodyUsed", {
get: function() {
return this._hasEnded;
}
})
// Original signature writeHead(statusCode[, statusMessage][, headers])
resp.writeHead = function(statusCode, ...args) {
let headers = args[args.length - 1];
// statusMessage is a string
if(typeof headers !== "string") {
this._contentType = getContentType(headers);
}
if((this._contentType || "").startsWith("text/html")) {
this._wrappedHeaders.push([statusCode, ...args]);
} else {
return this._wrappedOriginalWriteHead(statusCode, ...args);
}
return this;
}
// data can be a String or Buffer
resp.write = function(data, ...args) {
if(typeof data === "string") {
if(!this._writeCache) {
this._writeCache = "";
}
// TODO encoding and callback args
this._writeCache += data;
} else {
// Buffers
return this._wrappedOriginalWrite(data, ...args);
}
return this;
}
// data can be a String or Buffer
resp.end = function(data, encoding, callback) {
resp._hasEnded = true;
if(typeof this._writeCache === "string" || typeof data === "string") {
// Strings
if(!this._writeCache) {
this._writeCache = "";
}
if(typeof data === "string") {
this._writeCache += data;
}
let result = this._writeCache;
// Only transform HTML
// Note the “setHeader versus writeHead” note on https://nodejs.org/api/http.html#responsewriteheadstatuscode-statusmessage-headers
let contentType = this._contentType || getContentType(this.getHeaders());
if(contentType?.startsWith("text/html")) {
if(this._wrappedTransformHtml && typeof this._wrappedTransformHtml === "function") {
result = this._wrappedTransformHtml(result);
// uncompressed size: https://github.com/w3c/ServiceWorker/issues/339
this.setHeader("Content-Length", Buffer.byteLength(result));
}
}
for(let headers of this._wrappedHeaders) {
this._wrappedOriginalWriteHead(...headers);
}
this._writeCache = [];
this._wrappedOriginalWrite(result, encoding)
return this._wrappedOriginalEnd(callback);
} else {
// Buffer or Uint8Array
for(let headers of this._wrappedHeaders) {
this._wrappedOriginalWriteHead(...headers);
}
if(data) {
this._wrappedOriginalWrite(data, encoding);
}
return this._wrappedOriginalEnd(callback);
}
}
return resp;
}
module.exports = wrapResponse;
|
