Request.md

Fastify

Request

The first parameter of the handler function is Request.

Request is a core Fastify object containing the following fields:

• query - The parsed querystring, its format is specified by querystringParser.
• body - The request payload, see Content-Type Parser for details on what request payloads Fastify natively parses and how to support other content types.
• params - The params matching the URL.
• headers - The headers getter and setter.
• raw - The incoming HTTP request from Node core.
• server - The Fastify server instance, scoped to the current encapsulation context.
• id - The request ID.
• log - The logger instance of the incoming request.
• ip - The IP address of the incoming request.
• ips - An array of the IP addresses, ordered from closest to furthest, in the X-Forwarded-For header of the incoming request (only when the trustProxy option is enabled).
• host - The host of the incoming request (derived from X-Forwarded-Host header when the trustProxy option is enabled). For HTTP/2 compatibility, it returns :authority if no host header exists. The host header may return an empty string if requireHostHeader is false, not provided with HTTP/1.0, or removed by schema validation.
• hostname - The hostname derived from the host property of the incoming request.
• port - The port from the host property, which may refer to the port the server is listening on.
• protocol - The protocol of the incoming request (https or http).
• method - The method of the incoming request.
• url - The URL of the incoming request.
• originalUrl - Similar to url, allows access to the original url in case of internal re-routing.
• is404 - true if request is being handled by 404 handler, false otherwise.
• socket - The underlying connection of the incoming request.
• context - Deprecated, use request.routeOptions.config instead. A Fastify internal object. Do not use or modify it directly. It is useful to access one special key:
  • context.config - The route config object.
• routeOptions - The route option object.
  • bodyLimit - Either server limit or route limit.
  • config - The config object for this route.
  • method - The HTTP method for the route.
  • url - The path of the URL to match this route.
  • handler - The handler for this route.
  • attachValidation - Attach validationError to request (if there is a schema defined).
  • logLevel - Log level defined for this route.
  • schema - The JSON schemas definition for this route.
  • version - A semver compatible string that defines the version of the endpoint.
  • exposeHeadRoute - Creates a sibling HEAD route for any GET routes.
  • prefixTrailingSlash - String used to determine how to handle passing / as a route with a prefix.
• .getValidationFunction(schema | httpPart) - Returns a validation function for the specified schema or HTTP part, if set or cached.
• .compileValidationSchema(schema, [httpPart]) - Compiles the specified schema and returns a validation function using the default (or customized) ValidationCompiler. The optional httpPart is forwarded to the ValidationCompiler if provided, defaults to null.
• .validateInput(data, schema | httpPart, [httpPart]) - Validates the input using the specified schema and returns the serialized payload. If httpPart is provided, the function uses the serializer for that HTTP Status Code. Defaults to null.

Headers

The request.headers is a getter that returns an object with the headers of the incoming request. Set custom headers as follows:

request.headers = {
  'foo': 'bar',
  'baz': 'qux'
}

This operation adds new values to the request headers, accessible via request.headers.bar. Standard request headers remain accessible via request.raw.headers.

For performance reasons, Symbol('fastify.RequestAcceptVersion') may be added to headers on not found routes.

Note: Schema validation may mutate the request.headers and request.raw.headers objects, causing the headers to become empty.

fastify.post('/:params', options, function (request, reply) {
  console.log(request.body)
  console.log(request.query)
  console.log(request.params)
  console.log(request.headers)
  console.log(request.raw)
  console.log(request.server)
  console.log(request.id)
  console.log(request.ip)
  console.log(request.ips)
  console.log(request.host)
  console.log(request.hostname)
  console.log(request.port)
  console.log(request.protocol)
  console.log(request.url)
  console.log(request.routeOptions.method)
  console.log(request.routeOptions.bodyLimit)
  console.log(request.routeOptions.method)
  console.log(request.routeOptions.url)
  console.log(request.routeOptions.attachValidation)
  console.log(request.routeOptions.logLevel)
  console.log(request.routeOptions.version)
  console.log(request.routeOptions.exposeHeadRoute)
  console.log(request.routeOptions.prefixTrailingSlash)
  console.log(request.routeOptions.logLevel)
  request.log.info('some info')
})

.getValidationFunction(schema | httpPart)

By calling this function with a provided schema or httpPart, it returns a validation function to validate diverse inputs. It returns undefined if no serialization function is found using the provided inputs.

This function has an errors property. Errors encountered during the last validation are assigned to errors.

const validate = request
                  .getValidationFunction({
                    type: 'object',
                    properties: {
                      foo: {
                        type: 'string'
                      }
                    }
                  })
console.log(validate({ foo: 'bar' })) // true
console.log(validate.errors) // null

// or

const validate = request
                  .getValidationFunction('body')
console.log(validate({ foo: 0.5 })) // false
console.log(validate.errors) // validation errors

See .compileValidationSchema(schema, [httpStatus]) for more information on compiling validation schemas.

.compileValidationSchema(schema, [httpPart])

This function compiles a validation schema and returns a function to validate data. The returned function (a.k.a. validation function) is compiled using the provided SchemaController#ValidationCompiler. A WeakMap is used to cache this, reducing compilation calls.

The optional parameter httpPart, if provided, is forwarded to the ValidationCompiler, allowing it to compile the validation function if a custom ValidationCompiler is provided for the route.

This function has an errors property. Errors encountered during the last validation are assigned to errors.

const validate = request
                  .compileValidationSchema({
                    type: 'object',
                    properties: {
                      foo: {
                        type: 'string'
                      }
                    }
                  })
console.log(validate({ foo: 'bar' })) // true
console.log(validate.errors) // null

// or

const validate = request
                  .compileValidationSchema({
                    type: 'object',
                    properties: {
                      foo: {
                        type: 'string'
                      }
                    }
                  }, 200)
console.log(validate({ hello: 'world' })) // false
console.log(validate.errors) // validation errors

Be careful when using this function, as it caches compiled validation functions based on the provided schema. If schemas are mutated or changed, the validation functions will not detect the alterations and will reuse the previously compiled validation function, as the cache is based on the schema's reference.

If schema properties need to be changed, create a new schema object to benefit from the cache mechanism.

Using the following schema as an example:

const schema1 = {
  type: 'object',
  properties: {
    foo: {
      type: 'string'
    }
  }
}

Not

const validate = request.compileValidationSchema(schema1)

// Later on...
schema1.properties.foo.type. = 'integer'
const newValidate = request.compileValidationSchema(schema1)

console.log(newValidate === validate) // true

Instead

const validate = request.compileValidationSchema(schema1)

// Later on...
const newSchema = Object.assign({}, schema1)
newSchema.properties.foo.type = 'integer'

const newValidate = request.compileValidationSchema(newSchema)

console.log(newValidate === validate) // false

.validateInput(data, [schema | httpStatus], [httpStatus])

This function validates the input based on the provided schema or HTTP part. If both are provided, the httpPart parameter takes precedence.

If no validation function exists for a given schema, a new validation function will be compiled, forwarding the httpPart if provided.

request
  .validateInput({ foo: 'bar'}, {
    type: 'object',
    properties: {
      foo: {
        type: 'string'
      }
    }
  }) // true

// or

request
  .validateInput({ foo: 'bar'}, {
    type: 'object',
    properties: {
      foo: {
        type: 'string'
      }
    }
  }, 'body') // true

// or

request
  .validateInput({ hello: 'world'}, 'query') // false

See .compileValidationSchema(schema, [httpStatus]) for more information on compiling validation schemas.