|
| 1 | +/** |
| 2 | + * MHRV Hybrid Relay (Apps Script + optional Cloudflare Worker) |
| 3 | + * |
| 4 | + * Client protocol (same as mhrv-rs): |
| 5 | + * Single: POST { k, m, u, h, b, ct, r } -> { s, h, b } or { e } |
| 6 | + * Batch : POST { k, q: [{m,u,h,b,ct,r}, ...] } -> { q: [{s,h,b}|{e}, ...] } |
| 7 | + * |
| 8 | + * Routing: |
| 9 | + * - Default: direct UrlFetchApp to destination URL |
| 10 | + * - Optional CFW path: for hostnames listed in CFW_HOSTS, forward via WORKER_URL |
| 11 | + * |
| 12 | + * Notes: |
| 13 | + * - Keep AUTH_KEY secret and match it in mhrv-rs config. |
| 14 | + * - If WORKER_URL is empty, CFW route is effectively disabled. |
| 15 | + */ |
| 16 | + |
| 17 | +const AUTH_KEY = "CHANGE_ME_TO_A_STRONG_SECRET"; |
| 18 | + |
| 19 | +// Optional Cloudflare Worker endpoint (ex: "https://myrelay.workers.dev") |
| 20 | +const WORKER_URL = ""; |
| 21 | + |
| 22 | +// Optional host routing list for worker path. |
| 23 | +// Exact host: "x.com" |
| 24 | +// Suffix : ".twitter.com" (matches api.twitter.com) |
| 25 | +const CFW_HOSTS = [ |
| 26 | + // "x.com", |
| 27 | + // ".twitter.com", |
| 28 | +]; |
| 29 | + |
| 30 | +const SKIP_HEADERS = { |
| 31 | + host: 1, |
| 32 | + connection: 1, |
| 33 | + "content-length": 1, |
| 34 | + "transfer-encoding": 1, |
| 35 | + "proxy-connection": 1, |
| 36 | + "proxy-authorization": 1, |
| 37 | + "priority": 1, |
| 38 | + te: 1, |
| 39 | +}; |
| 40 | + |
| 41 | +const DECOY_HTML = |
| 42 | + '<!DOCTYPE html><html><head><title>Web App</title></head>' + |
| 43 | + '<body><p>The script completed but did not return anything.</p></body></html>'; |
| 44 | + |
| 45 | +function doPost(e) { |
| 46 | + try { |
| 47 | + var req = JSON.parse(e.postData.contents); |
| 48 | + if (req.k !== AUTH_KEY) return _decoy(); |
| 49 | + |
| 50 | + if (Array.isArray(req.q)) return _doBatch(req.q); |
| 51 | + return _doSingle(req); |
| 52 | + } catch (err) { |
| 53 | + return _decoy(); |
| 54 | + } |
| 55 | +} |
| 56 | + |
| 57 | +function doGet(e) { |
| 58 | + return ContentService.createTextOutput(DECOY_HTML).setMimeType(ContentService.MimeType.HTML); |
| 59 | +} |
| 60 | + |
| 61 | +function _doSingle(req) { |
| 62 | + if (!_isValidUrl(req.u)) return _json({ e: "bad url" }); |
| 63 | + |
| 64 | + try { |
| 65 | + var resp = _fetchRelay(req); |
| 66 | + return _json(_packResponse(resp)); |
| 67 | + } catch (err) { |
| 68 | + return _json({ e: String(err) }); |
| 69 | + } |
| 70 | +} |
| 71 | + |
| 72 | +function _doBatch(items) { |
| 73 | + var fetchArgs = []; |
| 74 | + var indexMap = []; |
| 75 | + var results = []; |
| 76 | + |
| 77 | + for (var i = 0; i < items.length; i++) { |
| 78 | + var item = items[i]; |
| 79 | + if (!_isValidUrl(item.u)) { |
| 80 | + results[i] = { e: "bad url" }; |
| 81 | + continue; |
| 82 | + } |
| 83 | + |
| 84 | + var built = _buildFetch(item); |
| 85 | + fetchArgs.push(built.opts); |
| 86 | + indexMap.push({ idx: i, worker: built.worker }); |
| 87 | + } |
| 88 | + |
| 89 | + if (fetchArgs.length > 0) { |
| 90 | + var responses = UrlFetchApp.fetchAll(fetchArgs); |
| 91 | + for (var j = 0; j < responses.length; j++) { |
| 92 | + var meta = indexMap[j]; |
| 93 | + try { |
| 94 | + if (meta.worker) { |
| 95 | + results[meta.idx] = JSON.parse(responses[j].getContentText()); |
| 96 | + } else { |
| 97 | + results[meta.idx] = _packResponse(responses[j]); |
| 98 | + } |
| 99 | + } catch (err) { |
| 100 | + results[meta.idx] = { e: "invalid worker response" }; |
| 101 | + } |
| 102 | + } |
| 103 | + } |
| 104 | + |
| 105 | + for (var k = 0; k < items.length; k++) { |
| 106 | + if (!results[k]) results[k] = { e: "unknown" }; |
| 107 | + } |
| 108 | + |
| 109 | + return _json({ q: results }); |
| 110 | +} |
| 111 | + |
| 112 | +function _fetchRelay(req) { |
| 113 | + var built = _buildFetch(req); |
| 114 | + var resp = UrlFetchApp.fetch(built.url, built.opts); |
| 115 | + if (!built.worker) return resp; |
| 116 | + |
| 117 | + var txt = resp.getContentText(); |
| 118 | + return { |
| 119 | + _worker: true, |
| 120 | + _parsed: JSON.parse(txt), |
| 121 | + }; |
| 122 | +} |
| 123 | + |
| 124 | +function _packResponse(resp) { |
| 125 | + if (resp && resp._worker) return resp._parsed; |
| 126 | + return { |
| 127 | + s: resp.getResponseCode(), |
| 128 | + h: _respHeaders(resp), |
| 129 | + b: Utilities.base64Encode(resp.getContent()), |
| 130 | + }; |
| 131 | +} |
| 132 | + |
| 133 | +function _buildFetch(req) { |
| 134 | + var useWorker = _shouldUseWorker(req.u); |
| 135 | + if (!useWorker) { |
| 136 | + return { |
| 137 | + url: req.u, |
| 138 | + worker: false, |
| 139 | + opts: _buildDirectOpts(req), |
| 140 | + }; |
| 141 | + } |
| 142 | + |
| 143 | + if (!WORKER_URL) { |
| 144 | + throw new Error("WORKER_URL is empty but request matched CFW_HOSTS"); |
| 145 | + } |
| 146 | + |
| 147 | + return { |
| 148 | + url: WORKER_URL, |
| 149 | + worker: true, |
| 150 | + opts: { |
| 151 | + method: "post", |
| 152 | + contentType: "application/json", |
| 153 | + payload: JSON.stringify(_buildWorkerPayload(req)), |
| 154 | + muteHttpExceptions: true, |
| 155 | + followRedirects: true, |
| 156 | + validateHttpsCertificates: true, |
| 157 | + escaping: false, |
| 158 | + }, |
| 159 | + }; |
| 160 | +} |
| 161 | + |
| 162 | +function _buildDirectOpts(req) { |
| 163 | + var opts = { |
| 164 | + method: (req.m || "GET").toLowerCase(), |
| 165 | + muteHttpExceptions: true, |
| 166 | + followRedirects: req.r !== false, |
| 167 | + validateHttpsCertificates: true, |
| 168 | + escaping: false, |
| 169 | + }; |
| 170 | + var headers = _filteredHeaders(req.h); |
| 171 | + if (Object.keys(headers).length > 0) opts.headers = headers; |
| 172 | + if (req.b) { |
| 173 | + opts.payload = Utilities.base64Decode(req.b); |
| 174 | + if (req.ct) opts.contentType = req.ct; |
| 175 | + } |
| 176 | + return opts; |
| 177 | +} |
| 178 | + |
| 179 | +function _buildWorkerPayload(req) { |
| 180 | + return { |
| 181 | + u: req.u, |
| 182 | + m: (req.m || "GET").toUpperCase(), |
| 183 | + h: _filteredHeaders(req.h), |
| 184 | + b: req.b || null, |
| 185 | + ct: req.ct || null, |
| 186 | + r: req.r !== false, |
| 187 | + }; |
| 188 | +} |
| 189 | + |
| 190 | +function _filteredHeaders(inHeaders) { |
| 191 | + var headers = {}; |
| 192 | + if (!inHeaders || typeof inHeaders !== "object") return headers; |
| 193 | + |
| 194 | + for (var k in inHeaders) { |
| 195 | + if (!inHeaders.hasOwnProperty(k)) continue; |
| 196 | + if (SKIP_HEADERS[k.toLowerCase()]) continue; |
| 197 | + headers[k] = inHeaders[k]; |
| 198 | + } |
| 199 | + return headers; |
| 200 | +} |
| 201 | + |
| 202 | +function _shouldUseWorker(url) { |
| 203 | + if (!CFW_HOSTS || CFW_HOSTS.length === 0) return false; |
| 204 | + |
| 205 | + var host; |
| 206 | + try { |
| 207 | + host = _hostFromUrl(url); |
| 208 | + } catch (_) { |
| 209 | + return false; |
| 210 | + } |
| 211 | + |
| 212 | + for (var i = 0; i < CFW_HOSTS.length; i++) { |
| 213 | + var entry = String(CFW_HOSTS[i] || "").trim().toLowerCase().replace(/\.+$/, ""); |
| 214 | + if (!entry) continue; |
| 215 | + if (entry.charAt(0) === ".") { |
| 216 | + var suffix = entry.slice(1); |
| 217 | + if (!suffix) continue; |
| 218 | + if (host === suffix || host.endsWith("." + suffix)) return true; |
| 219 | + } else { |
| 220 | + if (host === entry) return true; |
| 221 | + } |
| 222 | + } |
| 223 | + return false; |
| 224 | +} |
| 225 | + |
| 226 | +function _hostFromUrl(url) { |
| 227 | + var m = String(url || "").match(/^https?:\/\/([^\/]+)/i); |
| 228 | + if (!m) throw new Error("invalid url"); |
| 229 | + var authority = m[1].toLowerCase(); |
| 230 | + var noAuth = authority.indexOf("@") >= 0 ? authority.split("@").pop() : authority; |
| 231 | + if (noAuth.charAt(0) === "[") { |
| 232 | + var r = noAuth.indexOf("]"); |
| 233 | + return (r > 0 ? noAuth.slice(1, r) : noAuth).replace(/\.+$/, ""); |
| 234 | + } |
| 235 | + return noAuth.split(":")[0].replace(/\.+$/, ""); |
| 236 | +} |
| 237 | + |
| 238 | +function _isValidUrl(u) { |
| 239 | + return typeof u === "string" && /^https?:\/\//i.test(u); |
| 240 | +} |
| 241 | + |
| 242 | +function _respHeaders(resp) { |
| 243 | + try { |
| 244 | + if (typeof resp.getAllHeaders === "function") { |
| 245 | + return resp.getAllHeaders(); |
| 246 | + } |
| 247 | + } catch (_) {} |
| 248 | + return resp.getHeaders(); |
| 249 | +} |
| 250 | + |
| 251 | +function _decoy() { |
| 252 | + return ContentService.createTextOutput(DECOY_HTML).setMimeType(ContentService.MimeType.HTML); |
| 253 | +} |
| 254 | + |
| 255 | +function _json(obj) { |
| 256 | + return ContentService |
| 257 | + .createTextOutput(JSON.stringify(obj)) |
| 258 | + .setMimeType(ContentService.MimeType.JSON); |
| 259 | +} |
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