diff --git a/app.js b/app.js
index f6d5632b..f4bcd2e6 100755
--- a/app.js
+++ b/app.js
@@ -29,7 +29,7 @@ var nopt = require('nopt'),
     os = require('os'),
     props = require('./lib/properties'),
     compileHandler = require('./lib/compile').compileHandler,
-    diffHandler = require('./lib/diff').diffHandler,
+    buildDiffHandler = require('./lib/diff').buildDiffHandler,
     express = require('express'),
     child_process = require('child_process'),
     path = require('path'),
@@ -76,6 +76,11 @@ props.initialize(rootDir + '/config', propHierarchy);
 // in hidden object props.properties
 var gccProps = props.propsFor("gcc-explorer");
 
+// Read from gccexplorer's config the wdiff configuration
+// that will be used to configure lib/diff.js
+var wdiffConfig = {wdiffExe: gccProps('wdiff_exe'," /usr/bin/wdiff"),
+                   wdiffTmpDir: gccProps('wdiff_tmp_dir',"/tmp")};
+
 // Instantiate a function to access records concerning the chosen language
 // in hidden object props.properties
 var compilerPropsFunc = props.propsFor(language.toLowerCase());
@@ -415,7 +420,8 @@ findCompilers().then(function (compilers) {
         bodyParser = require('body-parser'),
         logger = require('morgan'),
         compression = require('compression'),
-        restreamer = require('./lib/restreamer');
+        restreamer = require('./lib/restreamer'),
+        diffHandler = buildDiffHandler(wdiffConfig);
 
     webServer
         .use(logger('combined'))
diff --git a/etc/config/gcc-explorer.defaults.properties b/etc/config/gcc-explorer.defaults.properties
index 1e362363..cd03738d 100644
--- a/etc/config/gcc-explorer.defaults.properties
+++ b/etc/config/gcc-explorer.defaults.properties
@@ -10,3 +10,6 @@ optionsWhitelistRe=.*
 optionsBlacklistRe=^(-W[alp],)?((-wrapper|-fplugin.*|-specs|-load|-plugin|(@.*)|-I|-i)(=.*)?|--)$
 allowedShortUrlHostRe=^([a-z]+\.)?(xania|godbolt)\.org$
 googleShortLinkRewrite=^https?://goo.gl/(.*)$|https://godbolt.org/g/$1
+
+wdiff_exe=../external/wdiff-1.2.2/src/wdiff
+wdiff_tmp_dir=/tmp
diff --git a/lib/diff.js b/lib/diff.js
index 1f320324..8d109751 100644
--- a/lib/diff.js
+++ b/lib/diff.js
@@ -137,62 +137,65 @@ function cleanAndGetIndexes(text) {
     return {text: finalText, zones: zones};
 }
 
-function diffHandler(req, res, next) {
-    // console.log("req: "+JSON.stringify(JSON.decycle(req)));
-    // console.log("");
-    // console.log("res: "+JSON.stringify(JSON.decycle(res)));
-    // console.log("");
-    // console.log("next: "+JSON.stringify(JSON.decycle(next)));
-    var before = req.body.before;
-    var after = req.body.after;
-    if (before === undefined) {
-        console.log("Warning : Bad request : wrong \"before\"");
-        //return next(new Error("Bad request : wrong \"before\""));
-    }
-    if (after === undefined) {
-        console.log("Warning : Bad request : wrong \"after\"");
-        //return next(new Error("Bad request : wrong \"after\""));
-    }
-    //console.log("Before: ");
-    //console.log(before);
-    //console.log("After: ");
-    //console.log(after);
-    // TODO : make async the two creation of temp files + call to wdiff
-    var before_temp_file = "/tmp/gcc-explorer-before"
-    fs.writeFileSync(before_temp_file, before);
-
-    var after_temp_file = "/tmp/gcc-explorer-after"
-    fs.writeFileSync(after_temp_file, after);
-
-    var wdiff_exe = "/work1/gdevillers/compiler-explorer/external/wdiff-1.2.2/src/wdiff";
-    var maxSize = 100000;
-    var wdiffResult = child_process.spawnSync(
-        "/work1/gdevillers/compiler-explorer/external/wdiff-1.2.2/src/wdiff", 
-        ["/tmp/gcc-explorer-before", "/tmp/gcc-explorer-after"],
-        {maxBuffer: 100000});
-
-    res.set('Content-Type', 'application/json');
-    var cleaned = cleanAndGetIndexes(wdiffResult.stdout.toString());
-    if (cleaned == null) {
-        res.end(JSON.stringify({
-            computedDiff: "Failed to clean the diff",
-            zones: null
-        }));
-    } else {
-    res.end(JSON.stringify({
-        computedDiff: cleaned.text,
-        //computedDiff: cleaned.text+
-        //    "\n//// for reference: ////\n"+ // for debug only
-        //    wdiffResult.stdout.toString(),
-        zones: cleaned.zones
-        //computedDiff: "aaa\nbbb[-ccc-]\n[-ddd-]eee\n[-fff-]\nsafe"
-        //computedDiff: "[-aaa-]"
-        //computedDiff: "aaa"
-        //computedDiff: "aa[--]a"
-        //computedDiff: "aa[-b-]"
-        }));
+function buildDiffHandler(config) {
+    return function diffHandler(req, res, next) {
+        // console.log("req: "+JSON.stringify(JSON.decycle(req)));
+        // console.log("");
+        // console.log("res: "+JSON.stringify(JSON.decycle(res)));
+        // console.log("");
+        // console.log("next: "+JSON.stringify(JSON.decycle(next)));
+        var before = req.body.before;
+        var after = req.body.after;
+        if (before === undefined) {
+            console.log("Warning : Bad request : wrong \"before\"");
+            //return next(new Error("Bad request : wrong \"before\""));
+        }
+        if (after === undefined) {
+            console.log("Warning : Bad request : wrong \"after\"");
+            //return next(new Error("Bad request : wrong \"after\""));
+        }
+        //console.log("Before: ");
+        //console.log(before);
+        //console.log("After: ");
+        //console.log(after);
+        
+        // TODO : make async the two creation of temp files + call to wdiff ?
+
+        var wdiffExe = config.wdiffExe;
+
+        var tempBeforePath = config.wdiffTmpDir + "/gcc-explorer-wdiff-before";
+        fs.writeFileSync(tempBeforePath, before);
+
+        var tempAfterPath = config.wdiffTmpDir + "/gcc-explorer-wdiff-after";
+        fs.writeFileSync(tempAfterPath, after);
+
+        // TODO : get rid of this buffer or calculate it...
+        var maxSize = 100000;
+        var wdiffResult = child_process.spawnSync(
+                wdiffExe, 
+                [tempBeforePath, tempAfterPath],
+                {maxBuffer: 100000});
+
+        res.set('Content-Type', 'application/json');
+        var cleaned = cleanAndGetIndexes(wdiffResult.stdout.toString());
+        if (cleaned == null) {
+            res.end(JSON.stringify({
+                computedDiff: "Failed to clean the diff",
+                zones: null
+            }));
+        } else {
+            res.end(JSON.stringify({
+                computedDiff: cleaned.text,
+                // for debug only:
+                //computedDiff: cleaned.text+
+                //    "\n//// for reference: ////\n"+
+                //    wdiffResult.stdout.toString(),
+                zones: cleaned.zones
+            }));
+        }
     }
 }
+
 module.exports = {
-    diffHandler: diffHandler,
+    buildDiffHandler: buildDiffHandler,
 };