Apollo CLI brings together your GraphQL clients and servers with tools for validating your schema, linting your operations for compatibility with your server, and generating static types for improved client-side type safety.
$ npm install -g apollo
$ apollo COMMAND
running command...
$ apollo (-v|--version|version)
apollo/1.4.0 darwin-x64 node-v10.4.1
$ apollo --help [COMMAND]
USAGE
$ apollo COMMAND
...apollo codegen:generate [OUTPUT]apollo help [COMMAND]apollo queries:checkapollo schema:checkapollo schema:download OUTPUTapollo schema:publish
Generate static types for GraphQL queries. Can use the published schema in Apollo Engine or a downloaded schema.
USAGE
$ apollo codegen:generate [OUTPUT]
ARGUMENTS
OUTPUT
Directory to which generated files will be written.
- For TypeScript/Flow generators, this specifies a directory relative to each source file by default.
- For TypeScript/Flow generators with the "outputFlat" flag is set, and for the Swift generator, this specifies a
file or directory (absolute or relative to the current working directory) to which:
- a file will be written for each query (if "output" is a directory)
- all generated types will be written
- For all other types, this defines a file (absolute or relative to the current working directory) to which all
generated types are written.
OPTIONS
-h, --help Show command help
--addTypename Automatically add __typename to your queries
--clientSchema=clientSchema Path to your client-side GraphQL schema file for `apollo-link-state`
(.graphql, .json, .js, .ts)
--customScalarsPrefix=customScalarsPrefix Include a prefix when using provided types for custom scalars
--key=key The API key for the Apollo Engine service
--mergeInFieldsFromFragmentSpreads Merge fragment fields onto its enclosing type
--namespace=namespace The namespace to emit generated code into.
--only=only Parse all input files, but only output generated code for the specified
file [Swift only]
--operationIdsPath=operationIdsPath Path to an operation id JSON map file. If specified, also stores the
operation ids (hashes) as properties on operation types [currently
Swift-only]
--outputFlat By default, TypeScript/Flow will put each generated file in a directory
next to its source file using the value of the "output" as the directory
name. Set "outputFlat" to put all generated files in the directory relative
to the current working directory defined by "output".
--passthroughCustomScalars Use your own types for custom scalars
--queries=queries [default: **/*.graphql] Path to your GraphQL queries, can include search
tokens like **
--schema=schema Path to your GraphQL schema (.graphql, .json, .js, .ts)
--tagName=tagName [default: gql] Name of the template literal tag used to identify template
literals containing GraphQL queries in Javascript/Typescript code
--target=target Type of code generator to use (swift | typescript | flow | scala), inferred
from output
--useFlowExactObjects Use Flow exact objects for generated types [flow only]
--useFlowReadOnlyTypes Use Flow read only types for generated types [flow only]
--watch Watch the query files to auto-generate on changes.
See code: src/commands/codegen/generate.ts
display help for apollo
USAGE
$ apollo help [COMMAND]
ARGUMENTS
COMMAND command to show help for
OPTIONS
--all see all commands in CLI
See code: @oclif/plugin-help
Checks your GraphQL operations for compatibility with the server. Checks against the published schema in Apollo Engine.
USAGE
$ apollo queries:check
OPTIONS
-h, --help Show command help
--json Output result as JSON
--key=key The API key for the Apollo Engine service
--queries=queries [default: **/*.graphql] Path to your GraphQL queries, can include search tokens like **
--tagName=tagName [default: gql] Name of the template literal tag used to identify template literals containing
GraphQL queries in Javascript/Typescript code
See code: src/commands/queries/check.ts
Check a schema against the version registered in Apollo Engine.
USAGE
$ apollo schema:check
OPTIONS
-h, --help Show command help
--endpoint=endpoint [default: http://localhost:4000/graphql] The URL of the server to fetch the schema from
--header=header Additional headers to send to server for introspectionQuery
--json Output result as JSON
--key=key The API key for the Apollo Engine service
See code: src/commands/schema/check.ts
Download the schema from your GraphQL endpoint.
USAGE
$ apollo schema:download OUTPUT
ARGUMENTS
OUTPUT [default: schema.json] Path to write the introspection result to
OPTIONS
-h, --help Show command help
--endpoint=endpoint [default: http://localhost:4000/graphql] The URL of the server to fetch the schema from or path
to ./your/local/schema.graphql
--header=header Additional headers to send to server for introspectionQuery
--key=key The API key for the Apollo Engine service
See code: src/commands/schema/download.ts
Publish a schema to Apollo Engine
USAGE
$ apollo schema:publish
OPTIONS
-h, --help Show command help
--endpoint=endpoint [default: http://localhost:4000/graphql] The URL of the server to fetch the schema from
--header=header Additional headers to send to server for introspectionQuery
--json Output successful publish result as JSON
--key=key The API key for the Apollo Engine service
See code: src/commands/schema/publish.ts
See Apollo iOS for details on the mapping from GraphQL results to Swift types, as well as runtime support for executing queries and mutations. For Scala, see React Apollo Scala.js for details on how to use generated Scala code in a Scala.js app with Apollo Client.
If the source file for generation is a JavaScript or TypeScript file, the codegen will try to extrapolate the queries inside the gql tag templates.
The tag name is configurable using the CLI --tagName option.
When using the codegen command with Typescript or Flow, make sure to add the __typename introspection field to every selection set within your graphql operations.
If you're using a client like apollo-client that does this automatically for your GraphQL operations, pass in the --addTypename option to apollo codegen:generate to make sure the generated Typescript and Flow types have the __typename field as well. This is required to ensure proper type generation support for GraphQLUnionType and GraphQLInterfaceType fields.
Using the type information from the GraphQL schema, we can infer the possible types for fields. However, in the case of a GraphQLUnionType or GraphQLInterfaceType, there are multiple types that are possible for that field. This is best modeled using a disjoint union with the __typename
as the discriminant.
For example, given a schema:
...
interface Character {
name: String!
}
type Human implements Character {
homePlanet: String
}
type Droid implements Character {
primaryFunction: String
}
...Whenever a field of type Character is encountered, it could be either a Human or Droid. Human and Droid objects
will have a different set of fields. Within your application code, when interacting with a Character you'll want to make sure to handle both of these cases.
Given this query:
query Characters {
characters(episode: NEW_HOPE) {
name
... on Human {
homePlanet
}
... on Droid {
primaryFunction
}
}
}Apollo Codegen will generate a union type for Character.
export type CharactersQuery = {
characters: Array<
| {
__typename: "Human",
name: string,
homePlanet: ?string
}
| {
__typename: "Droid",
name: string,
primaryFunction: ?string
}
>
};This type can then be used as follows to ensure that all possible types are handled:
function CharacterFigures({ characters }: CharactersQuery) {
return characters.map(character => {
switch (character.__typename) {
case "Human":
return (
<HumanFigure
homePlanet={character.homePlanet}
name={character.name}
/>
);
case "Droid":
return (
<DroidFigure
primaryFunction={character.primaryFunction}
name={character.name}
/>
);
}
});
}
This repo is composed of multiple packages managed by Lerna. The apollo-cli contains the core CLI commands. The apollo-codegen-core package contains all the compiler APIs needed to implement code generation support for new languages. The other apollo-codegen-* packages implement code generation support for individual languages.
Running tests locally:
npm install
npm test
You can also run npm commands within package folders after you have bootstrapped the repository (part of npm install).
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