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POUsing the request scope to store an object
 

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    <p>I'm using <a href="http://www.cfwheels.org" rel="nofollow">CFWheels</a> to develope an application in ColdFusion.</p> <p>I have a model called <code>Vote.cfc</code>. Before a Vote object can be created, updated, or deleted, I need to fetch a post object from another model: <code>Post.cfc</code>. A Vote belongs to a Post. A post has many votes.</p> <p>Using data from the <code>post</code> object, I need <code>to validate the vote</code> object across multiple criteria and several functions. The only way I can think of persisting the post object so that it's available to those functions is by storing it in the request scope.</p> <p>Others have said this is bad practice. But I was not able find out why. I thought the request scope was thread safe, and it would make sense to use it in this situation. </p> <p>My other alternative is to load a new instance of the post object in every function that requires it. Although Wheels uses caching, doing this caused request times to spike by 250%.</p> <h2>UPDATE</h2> <p>Here's some samples. First, the controller handles looking to see if a vote object already exists. If it does, it deletes it, if it does not, it creates it. The controller function is essentially a toggle function. </p> <p><strong>Votes.cfc Controller</strong></p> <pre><code> private void function toggleVote(required numeric postId, required numeric userId) { // First, we look for any existing vote like = model("voteLike").findOneByPostIdAndUserId(values="#arguments.postId#,#arguments.userId#"); // If no vote exists we create one if (! IsObject(like)) { like = model("voteLike").new(userId=arguments.userId, postId=arguments.postId); } else { like.delete() } } </code></pre> <p><strong>Model VoteLike.cfc</strong></p> <p>After that, a callback registered in the model fires before validation. It calls a function that retrieves the post object the vote will belong to. The function getPost() stores the post in the request scope. It is now made available to a bunch of validation functions in the model. </p> <pre><code>// Load post before Validation via callback in the Constructor beforeValidation("getPost"); private function getPost() { // this.postId will reference the post that the vote belongs to request.post = model("post").findByKey(this.postId); } // Validation function example private void function validatesIsNotOwnVote() { if (this.userId == request.post.userId) { // addError(message="You can't like your own post."); } } </code></pre> <p>The alternative to the getPost() function is to use a scoped call "<code>this.post().userId</code>" to get the post object, as such:</p> <pre><code>private void function validatesIsNotOwnVote() { if (this.userId == this.post().userId) { addError(message="can't vote on your own post") } } </code></pre> <p>But I would then have to repeat this scoped call <code>this.post().userId</code> for EVERY function, which is what I think is slowing down the request!</p>
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    1. CO@Mel: based on @Daniel Short's answer, and comments beneath, can you provide some clarification about how your code is structured?
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    2. CO@orangepips, I updated my question with some sample code!
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    3. COIs all validation done inside VoteLike.cfc? If so, then you can just set it to Variables.post = model("post").findByKey(this.postId), and then reference Variables.post instead of request.post.
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