fix(jsbattle-server): fix serving images

packages/jsbattle-server/.eslintrc.js

@@ -239,7 +239,6 @@ module.exports = {
         "require-atomic-updates": "error",
         "require-await": "error",
         "require-jsdoc": "off",
-        "require-unicode-regexp": "error",
         "rest-spread-spacing": "error",
         "semi": "off",
         "semi-spacing": "error",

packages/jsbattle-server/app/lib/stringReplaceMiddleware.js

@@ -0,0 +1,88 @@
+const hijackResponse = require('hijackresponse');
+const Transform = require('stream').Transform;
+const escapeStringRegexp = require('escape-string-regexp');
+
+const defaultOptions = {
+  contentTypeFilterRegexp: /^text\/|^application\/json$|^application\/xml$/,
+}
+
+module.exports = (replacements, options = defaultOptions ) => (req, res, next) => {
+    hijackResponse(res, (err, res) => {
+        const contentType = res.get('content-type');
+        if (options.contentTypeFilterRegexp.test(contentType)) {
+            if (err) {
+                res.unhijack();
+                return next(err);
+            }
+            res.removeHeader('Content-Length');
+            res
+                .pipe(stringReplaceStream(replacements))
+                .pipe(res);
+        } else {
+            return res.unhijack();
+        }
+    });
+    next();
+};
+
+function stringReplaceStream(replacements) {
+    const replacers = [];
+    const replace = (haystack, replacers, replaceBefore) => {
+        const getBody = (haystack) => haystack.slice(0, replaceBefore);
+        const tail = haystack.slice(replaceBefore);
+        replacers.forEach((replacer) => {
+            if (!replacer.matcher.test(haystack)) {
+                return;
+            }
+            haystack = getBody(haystack).replace(replacer.matcher, replacer.replace) + tail;
+        });
+        return [
+          getBody(haystack),
+          tail
+        ];
+    };
+    let tail = '';
+    let maxSearchLength = 0;
+
+    Object.keys(replacements)
+        .sort((str1, str2) => str2.length - str1.length)
+        .forEach((search) => {
+            maxSearchLength = Math.max(maxSearchLength, search.length);
+            replacers.push({
+                matcher: new RegExp(escapeStringRegexp(search), 'gmi'),
+                replace: replacements[search]
+            });
+        });
+
+    function transform(buf, enc, cb) {
+        const replaceBefore = maxSearchLength * 2;
+        let haystack = tail + buf.toString('utf8');
+        let body = '';
+
+        if (haystack.length + 2 < maxSearchLength * 3) {
+            tail = haystack;
+            cb(null, '');
+            return;
+        }
+
+        [
+          body,
+          tail
+        ] = replace(haystack, replacers, replaceBefore);
+
+        cb(null, body);
+    }
+
+    function flush(cb) {
+        if (tail) {
+            const result = replace(tail, replacers, tail.length);
+            this.push(result[0]);
+        }
+        cb();
+    }
+
+    return new Transform({
+        transform: transform,
+        flush: flush
+    });
+}

packages/jsbattle-server/app/services/Gateway.js

@@ -1,5 +1,5 @@
 const express = require('express');
-const stringReplace = require('string-replace-middleware');
+const stringReplace = require('../lib/stringReplaceMiddleware.js');
 const bodyParser = require('body-parser');
 const fs = require('fs');
 const path = require('path');