7.0 KiB
| title | summary |
|---|---|
| Configuring your schema | Add a basic type to the schema configuration |
Getting started
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Configuring your schema
GraphQL is a strongly-typed API layer, so having a schema behind it is essential. Simply put:
- A schema consists of types
- Types consist of fields
- Fields can have arguments.
- Fields need to resolve
Queries are just fields on a type called "query". They can take arguments, and they must resolve.
There's a bit more to it than that, and if you want to learn more about GraphQL, you can read the full documentation, but for now, these three concepts will serve almost all of your needs to get started.
Initial setup
To start your first schema, open a new configuration file. Let's call it graphql.yml.
app/_config/graphql.yml
SilverStripe\GraphQL\Schema\Schema:
schemas:
# your schemas here
Let's populate a schema that is pre-configured for us out of the box, default.
app/_config/graphql.yml
SilverStripe\GraphQL\Schema\Schema:
schemas:
default:
config:
# general schema config here
types:
# your generic types here
models:
# your dataobjects here
queries:
# your queries here
mutations:
# your mutations here
Avoid config flushes
Because the schema YAML is only consumed at build time and never used at runtime, it doesn't
make much sense to store it in the configuration layer, because it just means you'll
have to flush=1 every time you make a schema update, which will slow down your builds.
It is recommended that you store your schema YAML outside of the _config directory to increase performance and remove the need for flushing.
We can do this by adding a src key to our schema definition that maps to a directory
relative to the project root.
app/_config/graphql.yml
SilverStripe\GraphQL\Schema\Schema:
schemas:
default:
src: app/_graphql
[info] It is recommended that you define your sources as an array so that further source files are merged. Otherwise, another config file could completely override part of your schema definition. [/info]
app/_config/graphql.yml
SilverStripe\GraphQL\Schema\Schema:
schemas:
default:
src:
- app/_graphql
- module/_graphql
[info]
Your directory can also be a module reference, e.g. somevendor/somemodule: _graphql
[/info]
Now, in our app/_graphql file, we can create YAML file definitions.
[notice]
This doesn't mean there is never a need to flush your schema config. If you were to add a new
one, or make a change to the value of this src attribute, those are still a standard config changes.
[/notice]
app/_graphql/schema.yml
# no schema key needed. it's implied!
config:
# your schema config here
types:
# your generic types here
models:
# your dataobjects here
queries:
# your queries here
mutations:
# your mutations here
Namespacing your schema files
Your schema YAML file will get quite bloated if it's just used as a monolithic source of truth
like this. We can tidy this up quite a bit by simply placing the files in directories that map
to the keys they populate -- e.g. config/, types/, models/, queries/, mutations/, etc.
There are two approaches to namespacing:
- By filename
- By directory name
Namespacing by directory name
If you use a parent directory name (at any depth) of one of the four keywords above, it will be implicitly placed in the corresponding section of the schema.
app/_graphql/types/config.yml
# my schema config here
app/_graphql/types/types.yml
# my type definitions here
app/_graphql/models/models.yml
# my type definitions here
Namespacing by filename
If the filename is named one of the four keywords above, it will be implicitly placed in the corresponding section of the schema. This only works in the root source directory.
app/_graphql/types.yml
# my types here
app/_graphql/models.yml
# my models here
Going even more granular
These special directories can contain multiple files that will all merge together, so you can even create one file per type, or some other convention. All that matters is that the parent directory name matches one of the schema keys.
The following are perfectly valid:
app/_graphql/types/mySingleType.ymlapp/_graphql/models/allElementalBlocks.ymlapp/_graphql/news-and-blog/models/blog.ymlapp/_graphql/mySchema.yml
Schema config
In addition to all the keys mentioned above, each schema can declare a generic
configuration section, config. This are mostly used for assigning or removing plugins
and resolvers.
An important subsection of config is modelConfig, where you can configure settings for specific
models, e.g. DataObject.
Like the other sections, it can have its own config.yml, or just be added as a config:
mapping to a generic schema yaml document.
app/_graphql/config.yml
modelConfig:
DataObject:
plugins:
inheritance: true
operations:
read:
plugins:
readVersion: false
paginateList: false
Defining a basic type
Let's define a generic type for our GraphQL schema.
app/_graphql/types.yml*
Country:
fields:
name: String
code: String
population: Int
languages: '[String]'
If you're familiar with GraphQL type language, this should look pretty familiar. There are only a handful of scalar types available in GraphQL by default. They are:
- String
- Int
- Float
- Boolean
To define a type as a list, you wrap it in brackets: [String], [Int]
To define a type as required (non-null), you add an exclamation mark: String!
Often times, you may want to do both: [String!]!
[notice] Look out for the footgun, here. Make sure your bracketed type is in quotes, otherwise it's valid YAML that will get parsed as an array! [/notice]
That's all there is to it! To learn how we can take this further, check out the working with generic types documentation. Otherwise, let's get started on adding some dataobjects.
Further reading
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