From 6a19b99154b43903ba24d01fb61e509303ad2469 Mon Sep 17 00:00:00 2001
From: Christian Opitz <christian.opitz@netresearch.de>
Date: Sat, 25 Mar 2017 00:59:44 +0100
Subject: [PATCH] Added support for filter expressions from database paths to
 flashlight (firebase/flashlight#149) and added filter for invalid users

---
 flashlight.js            | 137 +++++++++++++++++++++++++++++++++++++++
 src/models/Config.js     |   2 +-
 src/models/Flashlight.js |   1 +
 3 files changed, 139 insertions(+), 1 deletion(-)

diff --git a/flashlight.js b/flashlight.js
index b7de350..80f358e 100644
--- a/flashlight.js
+++ b/flashlight.js
@@ -19,6 +19,143 @@ const fbrc = JSON.parse(fs.readFileSync('.firebaserc'));
   }
 });
 
+// That's so ugly but as flashlight doesn't export anything ¯\_(ツ)_/¯
+fs.appendFileSync('./lib/PathMonitor.js', '\n\nexports.PathMonitor = PathMonitor;');
+
+const vm = require('vm');
+require('colors');
+const PathMonitor = require('./lib/PathMonitor').PathMonitor;
+PathMonitor.prototype._process = function(fn, snap) {
+  const snVal = snap.val();
+  const snKey = snap.key;
+
+  if (fn === this._childRemoved) {
+    this._childRemoved(snKey, snVal);
+    if (this.filterRefs) {
+      const filterRefs = this.filterRefs;
+      Object.keys(filterRefs).forEach((path) => {
+        delete filterRefs[path].keys[key];
+        if (!Object.keys(filterRefs[path].keys).length) {
+          filterRefs[path].ref.off('value');
+          delete filterRefs[path];
+        }
+      });
+    }
+    return;
+  }
+
+  if (typeof this.filter === 'string') {
+    if (!this.filterScript) {
+      try {
+        this.filterScript = new vm.Script('RESULT = ' + this.filter, {
+          filename: this.ref.toString() + '/filter',
+          displayErrors: true
+        });
+      } catch (e) {
+        console.error('Error in filter expression:'.red);
+        console.error(e);
+        this.filter = () => false;
+        return;
+      }
+      this.filterRefs = {};
+    }
+
+    const filterRefs = this.filterRefs;
+    let load = {};
+    const invalidPathErrors = [];
+    const paths = {};
+    const context = vm.createContext({
+      ref: function (path) {
+        if (typeof path !== 'string' || !path) {
+          throw new Error('INVALID_PATH');
+        }
+        if (filterRefs[path]) {
+          paths[path] = true;
+          return filterRefs[path].val;
+        }
+        load[path] = true;
+        throw new Error('LOADING_REF');
+      },
+      data: snVal,
+      $id: snKey,
+      RESULT: false
+    });
+    const run = () => {
+      try {
+        this.filterScript.runInContext(context);
+      } catch (e) {
+        if (e.message === 'INVALID_PATH') {
+          if (invalidPathErrors.indexOf(e.toString()) < 0) {
+            invalidPathErrors.push(e.toString());
+          } else {
+            console.error('Invalid path at %s'.red, this.filter);
+            console.error(e);
+            return;
+          }
+        } else if (e.message !== 'LOADING_REF') {
+          console.error('Error at %s'.red, this.filter);
+          console.error(e);
+          return;
+        }
+      }
+      const promises = [];
+      Object.keys(load).forEach((path) => {
+        promises.push(new Promise((resolve, reject) => {
+          const ref = this.ref.root.child(path);
+          let initial = true;
+          ref.on('value', (sn) => {
+            if (initial) {
+              initial = false;
+              filterRefs[path] = { ref, keys: {}, val: sn.val() };
+              resolve();
+            } else {
+              filterRefs[path].val = sn.val();
+              Object.keys(filterRefs[path].keys).forEach((key) => {
+                this.ref.child(key).once('value', this._process.bind(
+                  this, filterRefs[path].keys[key] ? this._childChanged : this._childAdded
+                ));
+              });
+            }
+          }, (e) => {
+            console.error('Firebase error at %s'.red, this.filter);
+            console.error(e);
+            if (initial) {
+              initial = false;
+              reject();
+            }
+          });
+        }));
+      });
+      load = {};
+      if (promises.length) {
+        Promise.all(promises).then(run, () => {});
+      } else {
+        Object.keys(paths).forEach((path) => {
+          filterRefs[path].keys[snKey] = context.RESULT;
+        });
+        if (context.RESULT) {
+          fn.call(this, snKey, this.parse(snVal));
+        } else if (fn === this._childChanged) {
+          this._childRemoved(snKey, snVal);
+        }
+      }
+    };
+    run();
+  } else if (this.filter(snVal)) {
+    fn.call(this, snKey, this.parse(snVal));
+  }
+};
+PathMonitor.prototype._oldStop = PathMonitor.prototype._stop;
+PathMonitor.prototype._stop = function () {
+  this._oldStop();
+  if (this.filterRefs) {
+    Object.keys(this.filterRefs).forEach((path) => {
+      this.filterRefs[path].ref.off('value');
+    });
+    this.filterRefs = {};
+  }
+};
+
 module.exports = {
   paths: appConfig.flashlight.paths.paths || [],
 
diff --git a/src/models/Config.js b/src/models/Config.js
index 3b538f7..e21a2c0 100644
--- a/src/models/Config.js
+++ b/src/models/Config.js
@@ -97,7 +97,7 @@ const Config = {
   flashlight: {
     timeout: 3000,
     paths: {
-      paths: '/flashlight/paths',
+      paths: '/flashlight-test',
       queries: '/flashlight/queries',
       results: '/flashlight/results'
     }
diff --git a/src/models/Flashlight.js b/src/models/Flashlight.js
index 9daac3a..f3b5a6b 100644
--- a/src/models/Flashlight.js
+++ b/src/models/Flashlight.js
@@ -146,6 +146,7 @@ module.exports = class Flashlight {
         path: '/users/organizations/' + orgKey,
         index: orgKey,
         type: 'users',
+        filter: "['?', '!'].indexOf(ref('security/organizations/" + orgKey + "/users/' + $id)) < 0"
       };
     }
     return paths;