1 files changed, 133 insertions, 0 deletions
diff --git a/week-7/Final4/blog/posts.js b/week-7/Final4/blog/posts.js
new file mode 100644
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+++ b/week-7/Final4/blog/posts.js
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+/* The PostsDAO must be constructed with a connected database object */
+function PostsDAO(db) {
+    "use strict";
+
+    /* If this constructor is called without the "new" operator, "this" points
+     * to the global object. Log a warning and call it correctly. */
+    if (false === (this instanceof PostsDAO)) {
+        console.log('Warning: PostsDAO constructor called without "new" operator');
+        return new PostsDAO(db);
+    }
+
+    var posts = db.collection("posts");
+
+    this.insertEntry = function (title, body, tags, author, callback) {
+        "use strict";
+        console.log("inserting blog entry" + title + body);
+
+        // fix up the permalink to not include whitespace
+        var permalink = title.replace( /\s/g, '_' );
+        permalink = permalink.replace( /\W/g, '' );
+
+        // Build a new post
+        var post = {"title": title,
+                "author": author,
+                "body": body,
+                "permalink":permalink,
+                "tags": tags,
+                "comments": [],
+                "date": new Date()}
+
+        // now insert the post
+        posts.insert(post, function (err, result) {
+            "use strict";
+
+            if (err) return callback(err, null);
+
+            console.log("Inserted new post");
+            callback(err, permalink);
+        });
+    }
+
+    this.getPosts = function(num, callback) {
+        "use strict";
+
+        posts.find().sort('date', -1).limit(num).toArray(function(err, items) {
+            "use strict";
+
+            if (err) return callback(err, null);
+
+            console.log("Found " + items.length + " posts");
+
+            callback(err, items);
+        });
+    }
+
+    this.getPostsByTag = function(tag, num, callback) {
+        "use strict";
+
+        posts.find({ tags : tag }).sort('date', -1).limit(num).toArray(function(err, items) {
+            "use strict";
+
+            if (err) return callback(err, null);
+
+            console.log("Found " + items.length + " posts");
+
+            callback(err, items);
+        });
+    }
+
+    this.getPostByPermalink = function(permalink, callback) {
+        "use strict";
+        posts.findOne({'permalink': permalink}, function(err, post) {
+            "use strict";
+
+            if (err) return callback(err, null);
+
+            // XXX: Look here for final exam to see where we store "num_likes"
+
+            // fix up likes values. set to zero if data is not present
+            if (typeof post.comments === 'undefined') {
+                post.comments = [];
+            }
+
+            // Each comment document in a post should have a "num_likes" entry, so we have to
+            // iterate all the comments in the post to make sure that is the case
+            for (var i = 0; i < post.comments.length; i++) {
+                if (typeof post.comments[i].num_likes === 'undefined') {
+                    post.comments[i].num_likes = 0;
+                }
+                post.comments[i].comment_ordinal = i;
+            }
+            callback(err, post);
+        });
+    }
+
+    this.addComment = function(permalink, name, email, body, callback) {
+        "use strict";
+
+        var comment = {'author': name, 'body': body}
+
+        if (email != "") {
+            comment['email'] = email
+        }
+
+        posts.update({'permalink': permalink}, {'$push': {'comments': comment}}, function(err, numModified) {
+            "use strict";
+
+            if (err) return callback(err, null);
+
+            callback(err, numModified);
+        });
+    }
+
+    this.incrementLikes = function(permalink, comment_ordinal, callback) {
+        "use strict";
+
+        // The "comment_ordinal" argument specifies which comment in the post we are looking at
+        // Here is an example of how to build a selector with the 'comment_ordinal' variable
+        // We have to do it this way because a literal object with variables in field names such as:
+        // { 'comments.' + comment_ordinal + '.author' : 'Frank' } is illegal Javascript.
+        var selector_example = {};
+        var comment_ordinal_example = 0;
+        selector_example['comments.' + comment_ordinal_example + '.author'] = 'Frank';
+        // Now selector_example = { 'comments.0.author' : 'Frank' } which is a selector for the
+        // string 'Frank' in the 'author' field of the first element of the 'comments' array (which
+        // is zero indexed).
+
+        // TODO: Final exam question - Increment the number of likes
+        callback(Error("incrementLikes NYI"), null);
+    }
+}
+
+module.exports.PostsDAO = PostsDAO;