fire

README

Go on Fire

An idiomatic micro-framework for building Ember.js compatible APIs with Go.

Go on Fire is built on top of the wonderful built-in http package, implements the JSON API specification through the dedicated jsonapi library, uses the very stable mgo driver for persisting resources wit MongoDB and leverages the dedicated oauth2 library to provide out of the box support for OAuth2 authentication.

The deliberate and tight integration of these components provides a very simple and extensible set of abstractions for rapidly building backend services for websites that use Ember.js as their frontend framework. Of course it can also be used in conjunction with any other single page application framework or as a backend for native mobile applications.

An example application that uses Go on Fire to build an OAuth2 secured JSON API that is consumed by an Ember.js application can be found here: github.com/gonfire/example.

To quickly get started with building an API with Go on Fire follow the quickstart guide, read the detailed sections in this documentation and refer to the package documentation for more detailed information on the used types and methods.

License

The MIT License (MIT)

Copyright (c) 2016 Joël Gähwiler

Documentation

Index

• Constants
• func A(m Model, field string) string
• func C(m Model) string
• func Compose(chain ...interface{}) http.Handler
• func F(m Model, field string) string
• func Fatal(err error) error
• func Validate(m Model) error
• func ValidateTimestamps(m Model, createdAtField, updatedAtField string)
• type Action
  • func (a Action) Read() bool
  • func (a Action) Write() bool
• type Base
  • func (b *Base) ID() bson.ObjectId
  • func (b *Base) Meta() *Meta
  • func (b *Base) MustGet(name string) interface{}
  • func (b *Base) MustSet(name string, value interface{})
• type Callback
  • func DependentResourcesValidator(resources map[string]string) Callback
  • func Except(cb Callback, actions ...Action) Callback
  • func MatchingReferencesValidator(collection, reference string, matcher map[string]string) Callback
  • func ModelValidator() Callback
  • func Only(cb Callback, actions ...Action) Callback
  • func ProtectedAttributesValidator(attributes map[string]interface{}) Callback
  • func UniqueAttributeValidator(uniqueAttribute string, filters ...string) Callback
  • func VerifyReferencesValidator(references map[string]string) Callback
• type Context
  • func (c *Context) Original() (Model, error)
• type Controller
• type Field
• type Group
  • func NewGroup() *Group
  • func (g *Group) Add(controllers ...*Controller)
  • func (g *Group) Endpoint(prefix string) http.Handler
  • func (g *Group) Find(pluralName string) *Controller
  • func (g *Group) List() []*Controller
• type HasMany
• type Meta
  • func NewMeta(model Model) *Meta
  • func (m *Meta) FindField(name string) *Field
  • func (m *Meta) Make() Model
  • func (m *Meta) MakeSlice() interface{}
  • func (m *Meta) MustFindField(name string) *Field
• type Model
  • func Init(model Model) Model
  • func InitSlice(ptr interface{}) []Model
• type Store
  • func CreateStore(uri string) (*Store, error)
  • func MustCreateStore(uri string) *Store
  • func NewStore(session *mgo.Session) *Store
  • func (s *Store) C(model Model) *mgo.Collection
  • func (s *Store) Close()
  • func (s *Store) Copy() *Store
  • func (s *Store) DB() *mgo.Database
• type ValidatableModel

Constants

const NoDefault value = iota

NoDefault marks the specified field to have no default that needs to be enforced while executing the ProtectedAttributesValidator.

Functions

func A

func A(m Model, field string) string

A is a short-hand function to extract the JSON attribute name of a model attribute.

func C

func C(m Model) string

C is a short-hand function to extract the collection of a model.

func Compose

func Compose(chain ...interface{}) http.Handler

Compose is a short-hand for chaining the specified middlewares and handler together.

func F

func F(m Model, field string) string

F is a short-hand function to extract the BSON field name of a model attribute.

func Fatal

func Fatal(err error) error

Fatal wraps an error and marks it as fatal.

func Validate

func Validate(m Model) error

Validate uses the govalidator package to validate the model based on the "valid" struct tags. If the passed model also implements the ValidatableModel interface, Validate method will be invoked after the struct validation.

func ValidateTimestamps

func ValidateTimestamps(m Model, createdAtField, updatedAtField string)

ValidateTimestamps is a helper function that can be used inside a models Validate method to maintain "created-at" and "updated-at" timestamps.

Note: You can pass an empty string to disable certain timestamps.

Types

type Action

type Action int

An Action describes the currently called action on the API.

const (
	List Action
	Find
	Create
	Update
	Delete
)

All the available actions.

func (Action) Read

func (a Action) Read() bool

Read will return true when this action does only read data.

func (Action) Write

func (a Action) Write() bool

Write will return true when this action does write data.

type Base

type Base struct {
	DocID bson.ObjectId `json:"-" bson:"_id,omitempty"`
	// contains filtered or unexported fields
}

Base is the base for every fire model.

func (*Base) ID

func (b *Base) ID() bson.ObjectId

ID returns the models id.

func (*Base) Meta

func (b *Base) Meta() *Meta

Meta returns the models Meta structure.

func (*Base) MustGet

func (b *Base) MustGet(name string) interface{}

MustGet returns the value of the given field.

Note: MustGet will return the value of the first field that has a matching Name, JSONName, or BSONName and will panic if no field can be found.

func (*Base) MustSet

func (b *Base) MustSet(name string, value interface{})

MustSet will set the given field to the the passed valued.

Note: MustSet will set the value of the first field that has a matching Name, JSONName, or BSONName and will panic if no field can been found. The method will also panic if the type of the field and the passed value do not match.

type Callback

type Callback func(*Context) error

A Callback is called during execution of a controller.

Note: If the callback returns an error wrapped using Fatal() the API returns an InternalServerError status and the error will be logged. All other errors are serialized to an error object and returned.

func DependentResourcesValidator

func DependentResourcesValidator(resources map[string]string) Callback

DependentResourcesValidator counts documents in the supplied collections and returns an error if some get found. This callback is meant to protect resources from breaking relations when requested to be deleted.

Dependent resources are defined by passing pairs of collections and database fields that hold the current models id:

DependentResourcesValidator(map[string]string{
	C(&Post{}): F(&Post{}, "Author"),
	C(&Comment{}): F(&Comment{}, "Author"),
})

func Except

func Except(cb Callback, actions ...Action) Callback

Except will return a callback that runs the specified callback only when none of the supplied actions match.

func MatchingReferencesValidator

func MatchingReferencesValidator(collection, reference string, matcher map[string]string) Callback

MatchingReferencesValidator compares the model with a related model and checks if certain references are shared.

The target model is defined by passing its collection and the referencing field on the current model. The matcher is defined by passing pairs of database fields on the target and current model:

MatchingReferencesValidator(C(&Blog{}), F(&Post{}, "Blog"), map[string]string{
	F(&Blog{}, "Owner"): F(&Post{}, "Owner"),
})

func ModelValidator

func ModelValidator() Callback

ModelValidator performs a validation of the model using the Validate function.

func Only

func Only(cb Callback, actions ...Action) Callback

Only will return a callback that runs the specified callback only when one of the supplied actions match.

func ProtectedAttributesValidator

func ProtectedAttributesValidator(attributes map[string]interface{}) Callback

ProtectedAttributesValidator compares protected attributes against their default (during Create) or stored value (during Update) and returns an error if they have been changed.

Attributes are defined by passing pairs of fields and default values:

ProtectedAttributesValidator(map[string]interface{}{
	F(&Post{}, "Title"): NoDefault, // can only be set during Create
	F(&Post{}, "Link"):  "",        // is fixed and cannot be changed
})

The special NoDefault value can be provided to skip the default enforcement on Create.

func UniqueAttributeValidator

func UniqueAttributeValidator(uniqueAttribute string, filters ...string) Callback

UniqueAttributeValidator ensures that the specified attribute of the controllers Model will remain unique among the specified filters.

The unique attribute is defines as the first argument. Filters are defined by passing a list of database fields:

UniqueAttributeValidator(F(&Blog{}, "Name"), F(&Blog{}, "Creator"))

func VerifyReferencesValidator

func VerifyReferencesValidator(references map[string]string) Callback

VerifyReferencesValidator makes sure all references in the document are existing by counting the references on the related collections.

References are defined by passing pairs of database fields and collections of models whose ids might be referenced on the current model:

VerifyReferencesValidator(map[string]string{
	F(&Comment{}, "Post"): C(&Post{}),
	F(&Comment{}, "Author"): C(&User{}),
})

type Context

type Context struct {
	// The current action in process.
	Action Action

	// The query that will be used during List, Find, Update or Delete to fetch
	// a list of models or the specific requested model.
	//
	// On Find, Update and Delete, the "_id" key is preset to the document ID
	// while on List all field and relationship filters are preset.
	Query bson.M

	// The Model that will be saved during Create, updated during Update or
	// deleted during Delete.
	Model Model

	// The sorting that will be used during List.
	Sorting []string

	// The document that will be written to the client during List, Find, Create
	// and partially Update. The JSON API endpoints to modify a resources
	// relationships do only respond with a header as no other information should
	// be changed.
	Response *jsonapi.Document

	// The store that is used to retrieve and persist the model.
	Store *Store

	// The underlying JSON API request.
	JSONAPIRequest *jsonapi.Request

	// The underlying HTTP request.
	HTTPRequest *http.Request

	// The Controller that is managing the request.
	Controller *Controller

	// The Group that received the request.
	Group *Group
	// contains filtered or unexported fields
}

A Context provides useful contextual information.

func (*Context) Original

func (c *Context) Original() (Model, error)

Original will return the stored version of the model. This method is intended to be used to calculate the changed fields during an Update action. Any returned error is already marked as fatal.

Note: The method will panic if being used during any other action than Update.

type Controller

type Controller struct {
	// The model that this controller should provide (e.g. &Foo{}).
	Model Model

	// Filters defines the attributes that are filterable.
	Filters []string

	// Sorters defines the attributes that are sortable.
	Sorters []string

	// The store that is used to retrieve and persist the model.
	Store *Store

	// The Authorizers authorize the requested action on the requested resource
	// and are run before any models are loaded from the DB. Returned errors
	// will cause the abortion of the request with an Unauthorized status.
	//
	// The callbacks are expected to return an error if the requester should be
	// informed about him being unauthorized to access the resource or modify the
	// Context's Query attribute in such a way that only accessible resources
	// are returned. The later improves privacy as a protected resource would
	// just appear as being not found.
	Authorizers []Callback

	// The Validators are run to validate Create, Update and Delete actions after
	// the models are loaded from the DB and the changed attributes have been
	// assigned during an Update. Returned errors will cause the abortion of the
	// request with a Bad Request status.
	//
	// The callbacks are expected to validate the Model being created, updated or
	// deleted and return errors if the presented attributes or relationships
	// are invalid or do not comply with the stated requirements. The preceding
	// authorization checks should be repeated and now also include the model's
	// attributes and relationships.
	Validators []Callback

	// The Notifiers are run before the final response is written to the client
	// and provide a chance to modify the response and notify other systems
	// about the applied changes. Returned errors will cause the abortion of the
	// request with an Internal Server Error status.
	Notifiers []Callback

	// The NoList property can be set to true if the resource is only listed
	// through relationships from other resources. This is useful for
	// resources like comments that should never be listed alone.
	NoList bool

	// The ListLimit can be set to a value higher than 1 to enforce paginated
	// responses and restrain the page size to be within one and the limit.
	ListLimit int
}

A Controller provides a JSON API based interface to a model.

Note: Controllers must not be modified after adding to an application.

type Field

type Field struct {
	Name       string
	Type       reflect.Type
	Kind       reflect.Kind
	JSONName   string
	BSONName   string
	Optional   bool
	ToOne      bool
	ToMany     bool
	HasMany    bool
	RelName    string
	RelType    string
	RelInverse string
	// contains filtered or unexported fields
}

A Field contains the meta information about a single field of a model.

type Group

type Group struct {

	// The Reporter function gets invoked by the controller with any occurring
	// fatal errors.
	Reporter func(error)
	// contains filtered or unexported fields
}

A Group manages access to multiple controllers and their interconnections.

func NewGroup

func NewGroup() *Group

NewGroup creates and returns a new group.

func (*Group) Add

func (g *Group) Add(controllers ...*Controller)

Add will add a controller to the group.

func (*Group) Endpoint

func (g *Group) Endpoint(prefix string) http.Handler

Endpoint will return an http handler that serves requests for this controller group. The specified prefix is used to parse the requests and generate urls for the resources.

func (*Group) Find

func (g *Group) Find(pluralName string) *Controller

Find will return the controller with the matching plural name if found.

func (*Group) List

func (g *Group) List() []*Controller

List will return a list of all added controllers.

type HasMany

type HasMany struct{}

The HasMany type denotes a has many relationship in a model declaration.

type Meta

type Meta struct {
	Name       string
	PluralName string
	Collection string
	Fields     []Field
	// contains filtered or unexported fields
}

Meta stores extracted meta data from a model.

func NewMeta

func NewMeta(model Model) *Meta

NewMeta returns the Meta structure for the passed Model.

Note: This method panics if the passed Model has invalid fields and tags.

func (*Meta) FindField

func (m *Meta) FindField(name string) *Field

FindField returns the first field that has a matching Name, JSONName, or BSONName. FindField will return nil if no field has been found.

func (*Meta) Make

func (m *Meta) Make() Model

Make returns a pointer to a new zero initialized model e.g. *Post.

Note: Other libraries like mgo might replace the pointer content with a new structure, therefore the model eventually needs to be initialized again using Init().

func (*Meta) MakeSlice

func (m *Meta) MakeSlice() interface{}

MakeSlice returns a pointer to a zero length slice of the model e.g. *[]*Post.

Note: Don't forget to initialize the slice using InitSlice() after adding elements with libraries like mgo.

func (*Meta) MustFindField

func (m *Meta) MustFindField(name string) *Field

MustFindField returns the first field that has a matching Name, JSONName, or BSONName. MustFindField will panic if no field has been found.

type Model

type Model interface {
	ID() bson.ObjectId
	Meta() *Meta

	MustGet(string) interface{}
	MustSet(string, interface{})
	// contains filtered or unexported methods
}

Model is the main interface implemented by every fire model embedding Base.

func Init

func Init(model Model) Model

Init initializes the internals of a model and should be called before using a newly created Model.

func InitSlice

func InitSlice(ptr interface{}) []Model

InitSlice initializes all models in a slice of the form *[]*Post and returns a new slice that contains all initialized models.

type Store

type Store struct {
	// contains filtered or unexported fields
}

A Store manages the usage of database connections.

func CreateStore

func CreateStore(uri string) (*Store, error)

CreateStore will dial the passed database and return a new store. It will return an error if the initial connection failed

func MustCreateStore

func MustCreateStore(uri string) *Store

MustCreateStore will dial the passed database and return a new store. It will panic if the initial connection failed.

func NewStore

func NewStore(session *mgo.Session) *Store

NewStore returns a Store that uses the passed session and its default database.

func (*Store) C

func (s *Store) C(model Model) *mgo.Collection

C will return the collection associated to the passed model.

func (*Store) Close

func (s *Store) Close()

Close will close the store and its associated session.

func (*Store) Copy

func (s *Store) Copy() *Store

Copy will make a copy of the store and the underlying session. Copied stores that are not used anymore must be closed.

func (*Store) DB

func (s *Store) DB() *mgo.Database

DB returns the database used by this store.

type ValidatableModel

type ValidatableModel interface {
	Model

	// The Validate method that should return normal errors about invalid fields.
	Validate() error
}

The ValidatableModel interface can be additionally implemented to provide a custom validation method that is used by the Validate function.