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docs/ccxt/examples/js/proxy-round-robin.js

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+
+
+import ccxt from '../../js/ccxt.js';
+import asTable from 'as-table';
+import ololog from 'ololog';
+import ansicolor from 'ansicolor';
+
+const log = ololog.configure ({ locate: false })
+
+ansicolor.nice
+
+//-----------------------------------------------------------------------------
+
+// this script loads markets from all exchanges
+// if it cannot connect to an exchange, it falls back to an alternative route via proxy
+// it will retry to load a exchange until it either reaches the exchange or runs out of proxies
+
+//-----------------------------------------------------------------------------
+
+process.on ('uncaughtException',  e => { log.bright.red.error (e); process.exit (1) })
+process.on ('unhandledRejection', e => { log.bright.red.error (e); process.exit (1) })
+
+//-----------------------------------------------------------------------------
+
+let loadExchange = async exchange => {
+    await exchange.loadMarkets ()
+    log (exchange.id.green, 'loaded', 
+        exchange.symbols.length.toString ().bright.green, 'symbols', 
+        (exchange.proxy ? exchange.proxy : '_').blue)
+}
+
+//-----------------------------------------------------------------------------
+
+let tryAllProxies = async function (exchange, proxies) {
+
+    let currentProxy = 0
+    let maxRetries   = proxies.length
+
+    // a special case for ccex
+    if (exchange.id == 'ccex')
+        currentProxy = 1
+    
+    for (let numRetries = 0; numRetries < maxRetries; numRetries++) {
+
+        try {
+
+            exchange.proxy = proxies[currentProxy]
+            await loadExchange (exchange)
+            break
+
+        } catch (e) {
+
+            currentProxy = ++currentProxy % proxies.length
+            if (e instanceof ccxt.DDoSProtection) {
+                log.bright.yellow (exchange.id, '[DDoS Protection] ' + e.message)
+            } else if (e instanceof ccxt.RequestTimeout) {
+                log.bright.yellow (exchange.id, '[Request Timeout] ' + e.message)
+            } else if (e instanceof ccxt.AuthenticationError) {
+                log.bright.yellow (exchange.id, '[Authentication Error] ' + e.message)
+            } else if (e instanceof ccxt.ExchangeNotAvailable) {
+                log.bright.yellow (exchange.id, '[Exchange Not Available] ' + e.message)
+            } else if (e instanceof ccxt.ExchangeError) {
+                log.bright.yellow (exchange.id, '[Exchange Error] ' + e.message)
+            } else if (e instanceof ccxt.NetworkError) {
+                log.bright.yellow (exchange.id, '[Network Error] ' + e.message)
+            } else {
+                throw e;
+            }
+        }
+
+    }
+}
+
+//-----------------------------------------------------------------------------
+
+let proxies = [
+    '',
+    'https://cors-anywhere.herokuapp.com/',
+    'https://crossorigin.me/',
+]
+
+let exchanges = []
+
+async function main () {
+    // instantiate all exchanges
+    await Promise.all (ccxt.exchanges.map (async id => {
+        let exchange = new (ccxt)[id] ()
+        exchanges.push (exchange)
+        await tryAllProxies (exchange, proxies)
+    }))
+
+    let succeeded = exchanges.filter (exchange => exchange.markets ? true : false).length.toString ().bright.green
+    let failed = exchanges.filter (exchange => exchange.markets ? false : true).length
+    let total = ccxt.exchanges.length.toString ().bright.white
+    console.log (succeeded, 'of', total, 'exchanges loaded', ('(' + failed + ' errors)').red)
+}
+
+main ()