aboutsummaryrefslogtreecommitdiff
path: root/ext/bg/js/request-builder.js
blob: e438073494cf644ba3cb1a6d376aca8cd7365ccb (plain)
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
/*
 * Copyright (C) 2020  Yomichan Authors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

class RequestBuilder {
    constructor() {
        this._extraHeadersSupported = null;
        this._onBeforeSendHeadersExtraInfoSpec = ['blocking', 'requestHeaders', 'extraHeaders'];
    }

    async fetchAnonymous(url, init) {
        const originURL = this._getOriginURL(url);
        const modifications = [
            ['cookie', null],
            ['origin', {name: 'Origin', value: originURL}]
        ];
        return await this._fetchModifyHeaders(url, init, modifications);
    }

    // Private

    async _fetchModifyHeaders(url, init, modifications) {
        const matchURL = this._getMatchURL(url);

        let done = false;
        const callback = (details) => {
            if (done || details.url !== url) { return {}; }
            done = true;

            const requestHeaders = details.requestHeaders;
            this._modifyHeaders(requestHeaders, modifications);
            return {requestHeaders};
        };
        const filter = {
            urls: [matchURL],
            types: ['xmlhttprequest']
        };

        let needsCleanup = false;
        try {
            this._onBeforeSendHeadersAddListener(callback, filter);
            needsCleanup = true;
        } catch (e) {
            // NOP
        }

        try {
            return await fetch(url, init);
        } finally {
            if (needsCleanup) {
                try {
                    chrome.webRequest.onBeforeSendHeaders.removeListener(callback);
                } catch (e) {
                    // NOP
                }
            }
        }
    }

    _onBeforeSendHeadersAddListener(callback, filter) {
        const extraInfoSpec = this._onBeforeSendHeadersExtraInfoSpec;
        for (let i = 0; i < 2; ++i) {
            try {
                chrome.webRequest.onBeforeSendHeaders.addListener(callback, filter, extraInfoSpec);
                if (this._extraHeadersSupported === null) {
                    this._extraHeadersSupported = true;
                }
                break;
            } catch (e) {
                // Firefox doesn't support the 'extraHeaders' option and will throw the following error:
                // Type error for parameter extraInfoSpec (Error processing 2: Invalid enumeration value "extraHeaders") for webRequest.onBeforeSendHeaders.
                if (this._extraHeadersSupported !== null || !`${e.message}`.includes('extraHeaders')) {
                    throw e;
                }
            }

            // addListener failed; remove 'extraHeaders' from extraInfoSpec.
            this._extraHeadersSupported = false;
            const index = extraInfoSpec.indexOf('extraHeaders');
            if (index >= 0) { extraInfoSpec.splice(index, 1); }
        }
    }

    _getMatchURL(url) {
        const url2 = new URL(url);
        return `${url2.protocol}//${url2.host}${url2.pathname}`;
    }

    _getOriginURL(url) {
        const url2 = new URL(url);
        return `${url2.protocol}//${url2.host}`;
    }

    _modifyHeaders(headers, modifications) {
        modifications = new Map(modifications);

        for (let i = 0, ii = headers.length; i < ii; ++i) {
            const header = headers[i];
            const name = header.name.toLowerCase();
            const modification = modifications.get(name);
            if (typeof modification === 'undefined') { continue; }

            modifications.delete(name);

            if (modification === null) {
                headers.splice(i, 1);
                --i;
                --ii;
            } else {
                headers[i] = modification;
            }
        }

        for (const header of modifications.values()) {
            if (header !== null) {
                headers.push(header);
            }
        }
    }
}