-
Notifications
You must be signed in to change notification settings - Fork 2.1k
/
edge-handler-template.js
105 lines (97 loc) · 2.95 KB
/
edge-handler-template.js
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
// provided by the edge runtime:
/* global addEventListener */
function getUrl(url, headers) {
const urlObj = new URL(url);
const protocol = headers.get('x-forwarded-proto');
if (protocol) urlObj.protocol = protocol.split(/\b/).shift();
urlObj.host = headers.get('x-forwarded-host');
urlObj.port = headers.get('x-forwarded-port');
return urlObj.toString();
}
async function respond(handler, event, options, dependencies) {
const { Request, Response } = dependencies;
const { isMiddleware } = options;
event.request.headers.set(
'host',
event.request.headers.get('x-forwarded-host')
);
let response = await handler(
new Request(
getUrl(event.request.url, event.request.headers),
event.request
),
event
);
if (!response) {
if (isMiddleware) {
// allow empty responses to pass through
response = new Response(null, {
headers: {
'x-middleware-next': '1',
},
});
} else {
throw new Error(`Edge Function did not return a response.`);
}
}
return response;
}
function toResponseError(error, Response) {
// we can't easily show a meaningful stack trace
// so, stick to just the error message for now
const msg = error.cause
? error.message + ': ' + (error.cause.message || error.cause)
: error.message;
return new Response(msg, {
status: 500,
headers: {
'x-vercel-failed': 'edge-wrapper',
},
});
}
async function parseRequestEvent(event) {
const serializedRequest = await event.request.text();
const requestDetails = JSON.parse(serializedRequest);
return requestDetails;
}
// This will be invoked by logic using this template
// eslint-disable-next-line @typescript-eslint/no-unused-vars
function registerFetchListener(module, options, dependencies) {
let handler;
addEventListener('fetch', async event => {
try {
if (typeof module.default === 'function') {
handler = module.default;
} else {
if (
['GET', 'HEAD', 'OPTIONS', 'POST', 'PUT', 'DELETE', 'PATCH'].some(
method => typeof module[method] === 'function'
)
) {
const method = event.request.method ?? 'GET';
handler =
typeof module[method] === 'function'
? module[method]
: () => new dependencies.Response(null, { status: 405 });
}
}
if (!handler) {
const url = getUrl(event.request.url, event.request.headers);
throw new Error(
`No default or HTTP-named export was found at ${url}. Add one to handle requests. Learn more: https://vercel.link/creating-edge-middleware`
);
}
const response = await respond(handler, event, options, dependencies);
event.respondWith(response);
} catch (error) {
event.respondWith(toResponseError(error, dependencies.Response));
}
});
}
module.exports = {
getUrl,
parseRequestEvent,
registerFetchListener,
respond,
toResponseError,
};