Hydra - A Substrate query node framework
Inspired by The Graph, it gives a smooth way to provide powerful GraphQL queries to app developers over your Substrate blockchain state and history.
We make it simple
Slow Fetching
Doing multiple read operations across multiple block heights is often required, and the pure latency of fetching the data is very bad. Some reads may depend on the result of prior ones, which results in sequential reads, which is even slower.
Slow Processing
The client has to do all the work of filtering, sorting, paginating or otherwise computing on the resulting data, and this takes time, resulting in a slow client experience and CPU load on the user device.
Complex Client
The fetching and processing logic is reproduced in all apps, and adds to the complexity of application development.
No Search
Your chain may have transactional or state commitments to free-text data, but doing real full-text search client-side is not an option.
Over-Fetching
You cannot select the data you want, you have to read full state objects as they are, wasting both connection and full node capacity.
Costly Archival Nodes
User requests which involve multiple read operations. To fetch a consistent dataset, you will often have to read at some specific block height, as always reading at the tip can break atomicity. This means such read requests will depend on the full node being archival. As your user base scales, that will become a very costly infrastructure.
Powerful queries in GraphQL
{
hero {
name
# Queries can have comments!
friends {
name
}
}
}
{
"data" : {
"hero" : {
"name" : "R2-D2",
"friends" : [
{
"name" : "Luke Skywalker"
},
{
"name" : "Han Solo"
},
Hydra Features
Full-text Search
Decorate any number of String fields in the input schema with @fulltext(query: "myquery") to seach across different fields and entities.
Filtering
Pagination
Ordering
Polymorphism
Algebraic Types
# Input schema
type Post @entity {
text: String @fulltext(query: "forum-text-query"),
title: String @fulltext(query: "forum-text-query")
}
type Comment @entity {
text: String @fulltext(query: "forum-text-query"),
title: String @fulltext(query: "forum-text-query")
}