To use different subgraphs you need to change the url end point and GraphQL syntax. The sample Python code below contains a generic function that is used to make a post request to a subgraph. Next lets use a few of the queries that we constructed in The Graph’s Playground and use it in our Python code to request different data from the Ethereum blockchain. The far right side of the screen displays a list of fields that you can add to your query.The sample query is displayed and can be edited.This section of the website will allow you to construct and test out your GraphQL Ethereum blockchain queries. Make sure you experiment with the Playground. This service will execute your GraphQL queries.Ĥ. The http query address is needed in your Python code and is the endpoint that contains the blockchain data.Select a subgraph page and take notice of the http query address and the playground section of the page.Each one of these hosted services (subgraphs) can be queried for data. Visit The Graph Explorer to view all of the hosted subgraphs that exist for the Ethereum blockchain.Once a subgraph is deployed it can be queried using the GraphQL syntax.įor this tutorial we will focus on querying data from a subgraph. A subgraph defines which data The Graph will index from Ethereum, and how it will store it. It explains how to deploy a subgraph and how to query the subgraph for data. To get a better understanding of what The Graph project is and how it works visit /docs. Visit GraphQL to learn more about how to write complex GraphQL queries. This is essential to GraphQL and as a result the server knows exactly what fields the client is asking for. You can see that the query has the same structure as the result. The service checks the query to ensure it only refers to the types and fields defined, and then runs the function to produce a result.Īs an example view the structure of the query below: Once a GraphQL service is running, it can receive GraphQL queries to execute.
Let’s start by looking at a very simple GraphQL query structure and the results we get when we run it. GraphQL is about asking for specific fields from an object. This syntax isn’t tied to a specific type of database or storage engine and is instead backed by your existing code and data. The Graph (project) uses GraphQL which is a syntax language that describes how to ask for data. The project allows anyone to build and publish an open API called a subgraph The Graph is a blockchain project that uses the GraphQL query language.You can use The Graph to query systems like Ethereum, IPFS, etc.īefore we get started lets go over a few definitions: The Graph project is an indexing system for querying decentralized networks.
This is a step by step guide to help you use The Graph to query Ethereum data in Python.
0 kommentar(er)
