types.md

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Types

1Backend places a lot of focus on enabling the interoperability of different languages and tech stacks, since one of the biggest benefits of microservices is that you can use the best tool for a given job.

To achieve this, there is strong support for API definitions:

Every service has a "type" section where you can define the types living in your service. An example would be:

{
  "user": [{ "id": "string" }, { "name": "string" }],
  "product": [
    { "id": "string" },
    { "price": "float" },
    { "onSale": "bool" },
    { "inStock": "int" }
  ]
}

And each endpoint can refer to these types in their "input" and "output" sections.

An input section of a fictional "/products/on-sale" might look like:

[{ "priceMin": "float" }, { "priceMax": "float" }]

With the following output definition:

product[]

This will generate an Angular service method with the signature:

getProductsOnSale(priceMin: number, priceMax: number): Product[]

Unnamed types

The following built-in types are supported:

bool;
bool[];
string;
string[];
int;
int[];
float;
float[];

Named types

Named types are a list of field name -> type pairs. The type of a field can be another named type. See the "owner" field in the following example:

{
  "user": [{ "id": "string" }, { "name": "string" }],
  "product": [
    { "id": "string" },
    { "price": "float" },
    { "onSale": "bool" },
    { "inStock": "int" },
    { "owner": "User" }
  ]
}

Referring to named types from other services

Since services are designed to talk to each other, the picture would not be complete without a way to refer to types in other services:

{
  "product": [
    { "id": "string" },
    { "price": "float" },
    { "onSale": "bool" },
    { "inStock": "int" },
    { "owner": "crufter/user-service.User" }
  ]
}

As you can see, the syntax is "[User]/[ServiceName].[Type]".

List types

All types can be made into lists by appending [] to their names:

 { "owners": "crufter/user-service.User[]" }

Codebase pointers

You can find the code related to client generation in the api-pack directory.