Without writing a line of code get an instant high-performance GraphQL API for your Ruby-on-Rails app. Super Graph will automatically understand your apps database and expose a secure, fast and complete GraphQL API for it. Built in support for Rails authentication and JWT tokens.
We currently support the `query` action which is used for fetching data. Support for `mutation` and `subscriptions` is work in progress. For example the below GraphQL query would fetch two products that belong to the current user where the price is greater than 10
For example there is a while greater than `gt` and a limit clause on a child field. And the `avatar` field is renamed to `picture`. The `password` field is blocked and not returned. Finally the relationship between the `users` table and the `products` table is auto discovered and used.
In development mode you can use the `X-User-ID: 4` header to set a user id so you don't have to worries about cookies etc. This can be set using the *HTTP Headers* tab at the bottom of the web UI you'll see when you visit the above link. You can also directly run queries from the commandline like below.
#### Querying the GQL endpoint
```bash
# fetch the response json directly from the endpoint using user id 5
curl 'http://localhost:8080/api/v1/graphql' \
-H 'content-type: application/json' \
-H 'X-User-ID: 5' \
--data-binary '{"query":"{ products { name price users { email }}}"}'
```
## How to GraphQL
GraphQL (GQL) is a simple query syntax that's fast replacing REST APIs. GQL is great since it allows web developers to fetch the exact data that they need without depending on changes to backend code. Also if you squint hard enough it looks a little bit like JSON :smiley:
The below query will fetch an `users` name, email and avatar image (renamed as picture). If you also need the users `id` then just add it to the query.
To fetch a specific `product` by it's ID you can use the `id` argument. The real name id field will be resolved automatically so this query will work even if your id column is named something like `product_id`.
Postgres also supports full text search using a TSV index. Super Graph makes it easy to use this full text search capability using the `search` argument.
You will often find the need to fetch aggregated values from the database such as `count`, `max`, `min`, etc. This is simple to do with GraphQL, just prefix the aggregation name to the field name that you want to aggregrate like `count_id`. The below query will group products by name and find the minimum price for each group. Notice the `min_price` field we're adding `min_` to price.
All kinds of queries are possible with GraphQL. Below is an example that uses a lot of the features available. Comments `# hello` are also valid within queries.
Variables (`$product_id`) and their values (`"product_id": 5`) can be passed along side the GraphQL query. Using variables makes for better client side code as well as improved server side SQL query caching. The build-in web-ui also supports setting variables. Not having to manipulate your GraphQL query string to insert values into it makes for cleaner
Every app these days needs search. Enought his often means reaching for something heavy like Solr. While this will work why add complexity to your infrastructure when Postgres has really great
and fast full text search built-in. And since it's part of Postgres it's also available in Super Graph.
```graphql
query {
products(
# Search for all products that contain 'ale' or some version of it
search: "ale"
# Return only matches where the price is less than 10
# Use the search_rank to order from the best match to the worst
order_by: { search_rank: desc }) {
id
name
search_rank
search_headline_description
}
}
```
This query will use the `tsvector` column in your database table to search for products that contain the query phrase or some version of it. To get the internal relevance ranking for the search results using the `search_rank` field. And to get the highlighted context within any of the table columns you can use the `search_headline_` field prefix. For example `search_headline_name` will return the contents of the products name column which contains the matching query marked with the `<b></b>` html tags.
It's really easy to enable Postgres search on any table within your database schema. All it takes is to create the following migration. In the below example we add a full-text search to the `products` table.
```ruby
class AddSearchColumn <ActiveRecord::Migration[5.1]
def self.up
add_column :products, :tsv, :tsvector
add_index :products, :tsv, using: "gin"
say_with_time("Adding trigger to update the ts_vector column") do
execute <<-SQL
CREATE FUNCTION products_tsv_trigger() RETURNS trigger AS $$
It often happens that after fetching some data from the DB we need to call another API to fetch some more data and all this combined into a single JSON response. For example along with a list of users you need their last 5 payments from Stripe. This requires you to query your DB for the users and Stripe for the payments. Super Graph handles all this for you also only the fields you requested from the Stripe API are returned.
::: tip Is this fast?
Super Graph is able fetch remote data and merge it with the DB response in an efficient manner. Several optimizations such as parallel HTTP requests and a zero-allocation JSON merge algorithm makes this very fast. All of this without you having to write a line of code.
For example you need to list the last 3 payments made by a user. You will first need to look up the user in the database and then call the Stripe API to fetch his last 3 payments. For this to work your user table in the db has a `customer_id` column that contains his Stripe customer ID.
Similiarly you could also fetch the users last tweet, lead info from Salesforce or whatever else you need. It's fine to mix up several different `remote joins` into a single GraphQL query.
The configuration is self explanatory. A `payments` field has been added under the `customers` table. This field is added to the `remotes` subsection that defines fields associated with `customers` that are remote and not real database columns.
The `id` parameter maps a column from the `customers` table to the `$id` variable. In this case it maps `$id` to the `customer_id` column.
Just include `payments` like you would any other GraphQL selector under the `customers` selector. Super Graph will call the configured API for you and stitch (merge) the JSON the API sends back with the JSON generated from the database query. GraphQL features like aliases and fields all work.
```graphql
query {
customers {
id
email
payments {
customer_id
amount
billing_details
}
}
}
```
And voila here is the result. You get all of this advanced and honestly complex querying capability without writing a single line of code.
Even tracing data is availble in the Super Graph web UI if tracing is enabled in the config. By default it is enabled in development. Additionally there you can set `debug: true` to enable http request / response dumping to help with debugging.
stored in the users browser as a cookie, memcache or redis. If memcache or redis is used then a cookie is set in the users browser with just the session id.
Super Graph can handle all these variations including the old and new session formats. Just enable the right `auth` config based on how your rails app is configured.
For JWT tokens we currently support tokens from a provider like Auth0
or if you have a custom solution then we look for the `user_id` in the
`subject` claim of of the `id token`. If you pick Auth0 then we derive two variables from the token `user_id` and `user_id_provider` for to use in your filters.
We can get the JWT token either from the `authorization` header where we expect it to be a `bearer` token or if `cookie` is specified then we look there.
For validation a `secret` or a public key (ecdsa or rsa) is required. When using public keys they have to be in a PEM format file.
Configuration files can either be in YAML or JSON their names are derived from the `GO_ENV` variable, for example `GO_ENV=prod` will cause the `prod.yaml` config file to be used. or `GO_ENV=dev` will use the `dev.yaml`. A path to look for the config files in can be specified using the `-path <folder>` command line argument.
If deploying into environments like Kubernetes it's useful to be able to configure things like secrets and hosts though environment variables therfore we expose the below environment variables. This is escpecially useful for secrets since they are usually injected in via a secrets management framework ie. Kubernetes Secrets
Keep in mind any value can be overwritten using environment variables for example `auth.jwt.public_key_type` converts to `SG_AUTH_JWT_PUBLIC_KEY_TYPE`. In short prefix `SG_`, upper case and all `.` should changed to `_`.
If you want to build and run Super Graph from code then the below commands will build the web ui and launch Super Graph in developer mode with a watcher to rebuild on code changes. And the demo rails app is also launched to make it essier to test changes.
