GraphQL Recursive Query with Fragments

Although the GraphQL spec does not allow for recursive query definitions, we are able to extrapolate the subfield definitions into fragments and compose a recursive fragment definition that we can easily use in our Graph query definition. This article walks you through defining your recursive fragment and how to implement the fragment inside your GraphQL query.

We recently ran into a scenario where we wanted to create a GraphQL query that could recursively call children of a definition type. The use case was for a hierarchy of product categories on our site rustic.com where a category can be a parent and have children, and the children could have children etc. We discovered that GraphQL does not allow for recursive calls as per the specs.

It’s not possible to write a recursive query of unlimited depth. The graph of fragment spreads must not form any cycles including spreading itself. Otherwise an operation could infinitely spread or infinitely execute on cycles in the underlying data.

https://spec.graphql.org/

So how does one recursively call a GraphQL query if the query object is hierarchal and contains children? We do have to “plan” how deep our query will go but we can save ourselves a lot of time by using GraphQL Fragments. Fragments allow you to construct sets of repeatable fields, and then include them in queries where you need to.

#graphql #database

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How model queries work in Django

How model queries work in Django

Welcome to my blog, hey everyone in this article we are going to be working with queries in Django so for any web app that you build your going to want to write a query so you can retrieve information from your database so in this article I’ll be showing you all the different ways that you can write queries and it should cover about 90% of the cases that you’ll have when you’re writing your code the other 10% depend on your specific use case you may have to get more complicated but for the most part what I cover in this article should be able to help you so let’s start with the model that I have I’ve already created it.

**Read More : **How to make Chatbot in Python.

Read More : Django Admin Full Customization step by step

let’s just get into this diagram that I made so in here:

Describe each parameter in Django querset

we’re making a simple query for the myModel table so we want to pull out all the information in the database so we have this variable which is gonna hold a return value and we have our myModel models so this is simply the myModel model name so whatever you named your model just make sure you specify that and we’re gonna access the objects attribute once we get that object’s attribute we can simply use the all method and this will return all the information in the database so we’re gonna start with all and then we will go into getting single items filtering that data and go to our command prompt.

Here and we’ll actually start making our queries from here to do this let’s just go ahead and run** Python manage.py shell** and I am in my project file so make sure you’re in there when you start and what this does is it gives us an interactive shell to actually start working with our data so this is a lot like the Python shell but because we did manage.py it allows us to do things a Django way and actually query our database now open up the command prompt and let’s go ahead and start making our first queries.

#django #django model queries #django orm #django queries #django query #model django query #model query #query with django

What is a GraphQL query? GraphQL query examples using Apollo Explorer

How to execute GraphQL queries

We know what queries look like and we know what to expect in response when we write them. The next question is: how do we execute them?

It’s important to know that since GraphQL queries are just plain strings, we can use a variety of approaches to fetch data. Among the many options, some that come to mind are:

• curl
• fetch
• GraphQL client libraries (like Apollo Client)

#graphql #graphql query #apollo explorer

Securing Your GraphQL API from Malicious Queries

Depth Limiting
One harmful aspect of the malicious query above is the nesting, classified by its depth, which makes the query exponentially more expensive. Each layer adds a lot more work for your backend, which can quickly add up when combined with lists.

We looked around and found graphql-depth-limit, a lovely module by Andrew Carlson, which enables us to easily limit the maximum depth of incoming queries.

#security #graphql #graphql api #malicious queries

How to query with GraphQL? Is it really better than Rest?

Is GraphQL different from a database?

GraphQL is indeed different from databases like SQLite, MongoDB, and Firebase. It is a query language for APIs. While databases store data, GraphQL can help us fetch that data more efficiently. What makes GraphQL different from usual methods of fetching data is the amount of control we have.

Generally, we send a request to the database or the server asking for the required data. Even though the data might be organized in tables (like in SQLite) or some other format (like Firebase, where each data entry is a document), most of the time, we get more than what we may require. So it now comes to us to sift through that data and look for what we need.

#graphql #graphql queries #rest

While You Don't Understand Recursion, Read Recursion: by Randy Taylor

Recursion is the one idea I constantly use while I solve coding problems. Most of the time I don’t start by thinking “RECURSION WILL SOLVE THIS!”. However recursion just ends up being the logical way to reach an answer. In my professional opinion recursion is the purest form of coding; write a function that will call itself until you get what you want! To implement recursion we will create a helper algorithm. 1) Identify what the smallest input is. 2) Continually break down a larger input into smaller inputs and pass those smaller inputs back into itself until you get the desired answer. 3) Define a “base case” that will stop the Recursion should the answer not be found.

Let’s look at the idea of Recursion first. We are writing code that will execute itself until we get a desired answer or reach a base case. Essentially we are creating a loop. I will illustrate this with pseudo code:

for (let recursion =()=>{ …answer? answer = true : false} ; answer === false; recursion())

Much like a traditional for loop the above pseudo code will continue while the second condition is true; the recursion will continue until answer === true. At this point the second statement of the for loop is false terminating the loop. Above if answer === false recursion will call itself again. This is the general idea of recursion. This is why creating a base case is essential to prevent an infinite loop. The “answer” we are looking for might not be present causing recursion to run until the sun burns out.

#algorithms #javascript #recursion #tutorial-for-beginners #iteration #recursion-explained #what-is-recursion #programming