added support for popping elements from a collection

gilmaimon · Dec 20, 2018 · 6ee3efe · 6ee3efe
1 parent 243940c
commit 6ee3efe
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Showing 3 changed files with 95 additions and 3 deletions.
diff --git a/database-helpers/collections.js b/database-helpers/collections.js
@@ -53,7 +53,6 @@ class CollectionFetchRequest {
             this.request.skip = getNumberOrDefault(requestJson, 'skip', 0);
             this.request.from_last = requestJson.from_last? Boolean(requestJson.from_last) : false;
             this.request.collection_key = requestJson['collection_key'];
-            console.log(this.request);
             return true;
         } else return false;
     }
@@ -83,7 +82,6 @@ class CollectionFetchRequest {
             }}
         }
 
-        console.log(username);
         this.db.collection('users').aggregate([
             { $match : { "username" : username }},
             projectBlock,
@@ -94,7 +92,76 @@ class CollectionFetchRequest {
     }
 }
 
+class CollectionPopRequest {
+    constructor(db, requestJson) {
+        this.db = db;
+        this.__isValid = this.__parse(requestJson);
+    }
+
+    // Returns boolean value indicating if the request 
+    // is valid or not (result means isValid)
+    __parse(requestJson) {
+        if (requestJson.hasOwnProperty('collection_key') && requestJson.hasOwnProperty('position') &&
+            ["first", "last"].includes(requestJson.position) ) {
+            this.request = {}
+            this.request.position = requestJson['position'];
+            this.request.collection_key = requestJson['collection_key'];
+            return true;
+        } else return false;
+    }
+
+    isValid() {
+        return this.__isValid;
+    }
+
+    __popItem(username, collection_key, popFirstElement, value, willBeEmpty, callback) {
+        this.db.collection('users').updateOne({username: username}, {$pop: { ["data." + collection_key] : popFirstElement? -1: 1}}, function(err) {
+            callback(Boolean(err), {value: value, empty: willBeEmpty});
+        });
+    }
+
+    __getTop(username, collection_key, popFirstElement,  callback) {
+        this.db.collection('users').aggregate([
+            { $match: { username: username } },
+            { $project: {
+                topElements: { $slice: [ "$data." + collection_key, popFirstElement? 0 : -2, 2] },
+            }},
+        ]).toArray(function(err, res) {
+            if(err) {
+                callback(true, null);
+                return;
+            }
+            var value = null;
+            var empty = false;
+            if(res[0].topElements && res[0].topElements.length > 1) {
+                if(popFirstElement) value = res[0].topElements[0];
+                else value = res[0].topElements[1];
+            } else {
+                if(res[0].topElements) {
+                    value = res[0].topElements[0];
+                }
+                empty = true;
+            }
+
+            callback(value, empty);
+        })
+    }
+
+    execute(username, callback) {
+        if(!this.__isValid) throw Error("Requst is invalid (not parsed properly)");
+
+        var popFirstElement = this.request.position == "first";
+        var collection_key = this.request.collection_key
+        var that = this;
+
+        this.__getTop(username, collection_key, popFirstElement, function(value, willBeEmpty) {
+            that.__popItem(username, collection_key, popFirstElement, value, willBeEmpty, callback);
+        });
+    }
+}
+
 module.exports = {
     CollectionAddRequest: CollectionAddRequest,
-    CollectionFetchRequest: CollectionFetchRequest
+    CollectionFetchRequest: CollectionFetchRequest,
+    CollectionPopRequest: CollectionPopRequest
 }
diff --git a/database-helpers/users.js b/database-helpers/users.js
@@ -6,6 +6,7 @@ var getRequestFactory = new GetRequestFactory()
 
 const CollectionAddRequest = require('./collections').CollectionAddRequest;
 const CollectionFetchRequest = require('./collections').CollectionFetchRequest;
+const CollectionPopRequest = require('./collections').CollectionPopRequest;
 
 class User {
     constructor(db, username) {
@@ -48,6 +49,16 @@ class User {
 
         request.execute(this.username, callback);
     }
+
+    pop(requestJson, callback) {
+        var request = new CollectionPopRequest(this.db, requestJson);
+        if(request.isValid() == false) {
+            callback(false, null);
+            return;
+        }
+
+        request.execute(this.username, callback);
+    }
 }
 
 

diff --git a/main.js b/main.js
@@ -94,6 +94,7 @@ app.post('/data/collection', function (req, res) {
     res.send({"error": err});
    });
 });
+
 app.get('/data/collection', function(req, res) {
     req.userObj.filter(req.body, function(err, result) {
         if(err) {
@@ -107,6 +108,19 @@ app.get('/data/collection', function(req, res) {
     });
 });
 
+app.get('/data/collection/pop', function(req, res) {
+    req.userObj.pop(req.body, function(err, result) {
+        if(err) {
+            res.status(400).send({"error": true});
+        } else {
+            var parsedResult = {};
+            parsedResult.error = false;
+            parsedResult['result'] = result;
+            res.send(parsedResult);
+        }
+    });
+});
+
 // Route for Registering new users
 app.post('/user/register', function (req, res) {
     if(config.allow_registering) {