facebook

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 Go to latest Published: Oct 7, 2017 License: MIT Imports: 25 Imported by: 0

README

A Facebook Graph API SDK In Golang

Build Status

This is a Go package fully supports Facebook Graph API with file upload, batch request, marketing API. It can be used in Google App Engine.

API documents can be found on godoc.

Feel free to create an issue or send me a pull request if you have any "how-to" question or bug or suggestion when using this package. I'll try my best to reply it.

Get It

Use go get -u github.com/huandu/facebook to get or update it.

Usage

Quick start

Here is a sample that reads my Facebook first name by uid.

package main

import (
    "fmt"
    fb "github.com/huandu/facebook"
)

func main() {
    res, _ := fb.Get("/538744468", fb.Params{
        "fields": "first_name",
        "access_token": "a-valid-access-token",
    })
    fmt.Println("here is my facebook first name:", res["first_name"])
}

The type of res is fb.Result (a.k.a. map[string]interface{}). This type has several useful methods to decode res to any Go type safely.

// Decode "first_name" to a Go string.
var first_name string
res.DecodeField("first_name", &first_name)
fmt.Println("alternative way to get first_name:", first_name)

// It's also possible to decode the whole result into a predefined struct.
type User struct {
    FirstName string
}

var user User
res.Decode(&user)
fmt.Println("print first_name in struct:", user.FirstName)

If a type implements the json.Unmarshaler interface, Decode or DecodeField will use it to unmarshal JSON.

res := Result{
    "create_time": "2006-01-02T15:16:17Z",
}

// Type `*time.Time` implements `json.Unmarshaler`.
// res.DecodeField will use the interface to unmarshal data.
var tm time.Time
res.DecodeField("create_time", &tm)
Read a graph user object with a valid access token
res, err := fb.Get("/me/feed", fb.Params{
     "access_token": "a-valid-access-token",
})

if err != nil {
    // err can be an facebook API error.
    // if so, the Error struct contains error details.
    if e, ok := err.(*Error); ok {
        fmt.Printf("facebook error. [message:%v] [type:%v] [code:%v] [subcode:%v]",
            e.Message, e.Type, e.Code, e.ErrorSubcode)
        return
    }

    return
}

// read my last feed.
fmt.Println("my latest feed story is:", res.Get("data.0.story"))
Read a graph search for page and decode slice of maps
res, _ := fb.Get("/search", fb.Params{
        "access_token": "a-valid-access-token",
        "type":         "page",
        "q":            "nightlife,singapore",
    })

var items []fb.Result

err := res.DecodeField("data", &items)

if err != nil {
    fmt.Printf("An error has happened %v", err)
    return
}

for _, item := range items {
    fmt.Println(item["id"])
}
Use App and Session

It's recommended to use App and Session in a production app. They provide more control over all API calls. They can also make code clear and concise.

// create a global App var to hold app id and secret.
var globalApp = fb.New("your-app-id", "your-app-secret")

// facebook asks for a valid redirect uri when parsing signed request.
// it's a new enforced policy starting in late 2013.
globalApp.RedirectUri = "http://your.site/canvas/url/"

// here comes a client with a facebook signed request string in query string.
// creates a new session with signed request.
session, _ := globalApp.SessionFromSignedRequest(signedRequest)

// if there is another way to get decoded access token,
// creates a session directly with the token.
session := globalApp.Session(token)

// validate access token. err is nil if token is valid.
err := session.Validate()

// use session to send api request with access token.
res, _ := session.Get("/me/feed", nil)
Use paging field in response.

Some Graph API responses use a special JSON structure to provide paging information. Use Result.Paging() to walk through all data in such results.

res, _ := session.Get("/me/home", nil)

// create a paging structure.
paging, _ := res.Paging(session)

// get current results.
results := paging.Data()

// get next page.
noMore, err := paging.Next()
results = paging.Data()
Read graph API response and decode result into a struct

As facebook Graph API always uses lower case words as keys in API response. This package can convert go's camel-case-style struct field name to facebook's underscore-style API key name.

For instance, to decode following JSON response...

{
    "foo_bar": "player"
}

One can use following struct.

type Data struct {
    FooBar string  // "FooBar" maps to "foo_bar" in JSON automatically in this case.
}

The decoding of each struct field can be customized by the format string stored under the "facebook" key or the "json" key in the struct field's tag. The "facebook" key is recommended as it's specifically designed for this package.

Following is a sample shows all possible field tags.

// define a facebook feed object.
type FacebookFeed struct {
    Id          string            `facebook:",required"`             // this field must exist in response.
                                                                     // mind the "," before "required".
    Story       string
    FeedFrom    *FacebookFeedFrom `facebook:"from"`                  // use customized field name "from".
    CreatedTime string            `facebook:"created_time,required"` // both customized field name and "required" flag.
    Omitted     string            `facebook:"-"`                     // this field is omitted when decoding.
}

type FacebookFeedFrom struct {
    Name string `json:"name"`                   // the "json" key also works as expected.
    Id string   `facebook:"id" json:"shadowed"` // if both "facebook" and "json" key are set, the "facebook" key is used.
}

// create a feed object direct from graph api result.
var feed FacebookFeed
res, _ := session.Get("/me/feed", nil)
res.DecodeField("data.0", &feed) // read latest feed
Send a batch request
params1 := Params{
    "method": fb.GET,
    "relative_url": "me",
}
params2 := Params{
    "method": fb.GET,
    "relative_url": uint64(100002828925788),
}
results, err := fb.BatchApi(your_access_token, params1, params2)

if err != nil {
    // check error...
    return
}

// batchResult1 and batchResult2 are response for params1 and params2.
batchResult1, _ := results[0].Batch()
batchResult2, _ := results[1].Batch()

// Use parsed result.
var id string
res := batchResult1.Result
res.DecodeField("id", &id)

// Use response header.
contentType := batchResult1.Header.Get("Content-Type")
Use it in Google App Engine

Google App Engine provides appengine/urlfetch package as the standard http client package. The default client in net/http doesn't work. One must explicitly set http client in Session to make it work.

import (
    "appengine"
    "appengine/urlfetch"
)

// suppose it's the appengine context initialized somewhere.
var context appengine.Context

// default Session object uses http.DefaultClient which is not allowed to use
// in appengine. one has to create a Session and assign it a special client.
seesion := globalApp.Session("a-access-token")
session.HttpClient = urlfetch.Client(context)

// now, session uses appengine http client now.
res, err := session.Get("/me", nil)
Select Graph API version

See Platform Versioning to understand facebook versioning strategy.

// this package uses default version which is controlled by facebook app setting.
// change following global variable to specific a global default version.
fb.Version = "v2.0"

// starting with graph API v2.0; it's not allowed to get user information without access token.
fb.Api("huan.du", GET, nil)

// it's possible to specify version per session.
session := &fb.Session{}
session.Version = "v2.0" // overwrite global default.
Enable appsecret_proof

Facebook can verify Graph API Calls with appsecret_proof. It's a feature to make Graph API call more secure. See Securing Graph API Requests to know more about it.

globalApp := fb.New("your-app-id", "your-app-secret")

// enable "appsecret_proof" for all sessions created by this app.
globalApp.EnableAppsecretProof = true

// all calls in this session are secured.
session := globalApp.Session("a-valid-access-token")
session.Get("/me", nil)

// it's also possible to enable/disable this feature per session.
session.EnableAppsecretProof(false)
Debugging API Requests

Facebook introduces a way to debug graph API calls. See Debugging API Requests for details.

This package provides both package level, and per session debug flag. Set Debug to a DEBUG_* constant to change debug mode globally; or use Session#SetDebug to change debug mode for one session.

When debug mode is turned on, use Result#DebugInfo to get DebugInfo struct from the result.

fb.Debug = fb.DEBUG_ALL

res, _ := fb.Get("/me", fb.Params{"access_token": "xxx"})
debugInfo := res.DebugInfo()

fmt.Println("http headers:", debugInfo.Header)
fmt.Println("facebook api version:", debugInfo.FacebookApiVersion)
Work with package golang.org/x/oauth2

Package golang.org/x/oauth2 can handle facebook OAuth2 authentication process and access token very well. This package can work with it by setting Session#HttpClient to OAuth2's client.

import (
    "golang.org/x/oauth2"
    oauth2fb "golang.org/x/oauth2/facebook"
    fb "github.com/huandu/facebook"
)

// Get facebook access token.
conf := &oauth2.Config{
    ClientID:     "AppId",
    ClientSecret: "AppSecret",
    RedirectURL:  "CallbackURL",
    Scopes:       []string{"email"},
    Endpoint:     oauth2fb.Endpoint,
}
token, err := conf.Exchange(oauth2.NoContext, "code")

// Create a client to manage access token life cycle.
client := conf.Client(oauth2.NoContext, token)

// Use OAuth2 client with session.
session := &fb.Session{
    Version:    "v2.4",
    HttpClient: client,
}

// Use session.
res, _ := session.Get("/me", nil)
Control timeout and cancelation with Context

The Session can work with Context now.

// Create a new context.
ctx, cancel := context.WithTimeout(session.Context(), 100 * time.Millisecond)
defer cancel()

// Call an API with ctx.
// The return value of `session.WithContext` is a shadow copy of original session and
// should not be stored. It can be used only once.
result, err := session.WithContext(ctx).Get("/me", nil)

See https://blog.golang.org/context for more details about how to use Context.

Change Log

See CHANGELOG.md.

Out of Scope

  1. No OAuth integration. This package only provides APIs to parse/verify access token and code generated in OAuth 2.0 authentication process.
  2. No old RESTful API and FQL support. Such APIs are deprecated for years. Forget about them.

License

This package is licensed under MIT license. See LICENSE for details.

Documentation

Overview

This is a Go library fully supports Facebook Graph API (both 1.0 and 2.x) with file upload, batch request, FQL and multi-FQL. It can be used in Google App Engine.

Library design is highly influenced by facebook official PHP/JS SDK. If you have experience with PHP/JS SDK, you may feel quite familiar with it.

Go to project home page to see samples. Link: https://github.com/huandu/facebook

This library doesn't implement any deprecated old RESTful API. And it won't.

Index

Constants

View Source 
const (
	ERROR_CODE_UNKNOWN = -1 // unknown facebook graph api error code.

)

Variables

View Source 
var (
	// Default facebook api version.
	// It can be any valid version string (e.g. "v2.3") or empty.
	//
	// See https://developers.facebook.com/docs/apps/versions for details.
	Version string

	// Set app level debug mode.
	// After setting DebugMode, all newly created session will use the mode
	// to communicate with graph API.
	//
	// See https://developers.facebook.com/docs/graph-api/using-graph-api/v2.3#debugging
	Debug DebugMode
)

Functions

func Data 

func Data(filename string, source io.Reader) *binaryData

Creates new binary data holder.

func DataWithContentType added in v1.8.0 

func DataWithContentType(filename string, source io.Reader, contentType string) *binaryData

Creates new binary data holder with arbitrary content type.

func File 

func File(filename string) *binaryFile

Creates a binary file holder.

func FileAlias 

func FileAlias(filename, path string) *binaryFile

Creates a binary file holder and specific a different path for reading.

func FileAliasWithContentType added in v1.8.0 

func FileAliasWithContentType(filename, path, contentType string) *binaryFile

Creates a new binary file holder with arbitrary content type.

func SetHttpClient added in v1.5.0 

func SetHttpClient(client HttpClient)

SetHttpClient updates the http client of default session.

Types

type App 

type App struct {
	// Facebook app id
	AppId string

	// Facebook app secret
	AppSecret string

	// Facebook app redirect URI in the app's configuration.
	RedirectUri string

	// Enable appsecret proof in every API call to facebook.
	// Facebook document: https://developers.facebook.com/docs/graph-api/securing-requests
	EnableAppsecretProof bool
}

Holds facebook application information.

func New 

func New(appId, appSecret string) *App

Creates a new App and sets app id and secret.

func (*App) AppAccessToken 

func (app *App) AppAccessToken() string

Gets application access token, useful for gathering public information about users and applications.

func (*App) ExchangeToken 

func (app *App) ExchangeToken(accessToken string) (token string, expires int, err error)

Exchange a short-lived access token to a long-lived access token. Return new access token and its expires time.

func (*App) GetCode 

func (app *App) GetCode(accessToken string) (code string, err error)

Get code from a long lived access token. Return the code retrieved from facebook.

func (*App) ParseCode 

func (app *App) ParseCode(code string) (token string, err error)

ParseCode redeems code for a valid access token. It's a shorthand call to ParseCodeInfo(code, "").

In facebook PHP SDK, there is a CSRF state to avoid attack. That state is not checked in this library. Caller is responsible to store and check state if possible.

func (*App) ParseCodeInfo added in v1.5.0 

func (app *App) ParseCodeInfo(code, machineId string) (token string, expires int, newMachineId string, err error)

ParseCodeInfo redeems code for access token and returns extra information. The machineId is optional.

See https://developers.facebook.com/docs/facebook-login/access-tokens#extending

func (*App) ParseSignedRequest 

func (app *App) ParseSignedRequest(signedRequest string) (res Result, err error)

Parses signed request.

func (*App) Session 

func (app *App) Session(accessToken string) *Session

Creates a session based on current App setting.

func (*App) SessionFromSignedRequest 

func (app *App) SessionFromSignedRequest(signedRequest string) (session *Session, err error)

Creates a session from a signed request. If signed request contains a code, it will automatically use this code to exchange a valid access token.

type BatchResult added in v1.3.0 

type BatchResult struct {
	StatusCode int         // HTTP status code.
	Header     http.Header // HTTP response headers.
	Body       string      // Raw HTTP response body string.
	Result     Result      // Facebook api result parsed from body.
}

Represents facebook batch API call result. See https://developers.facebook.com/docs/graph-api/making-multiple-requests/#multiple_methods.

type DebugInfo added in v1.5.0 

type DebugInfo struct {
	Messages []DebugMessage // debug messages. it can be nil if there is no message.
	Header   http.Header    // all HTTP headers for this response.
	Proto    string         // HTTP protocol name for this response.

	// Facebook debug HTTP headers.
	FacebookApiVersion string // the actual graph API version provided by facebook-api-version HTTP header.
	FacebookDebug      string // the X-FB-Debug HTTP header.
	FacebookRev        string // the x-fb-rev HTTP header.
}

DebugInfo is the debug information returned by facebook when debug mode is enabled.

type DebugMessage added in v1.5.0 

type DebugMessage struct {
	Type    string
	Message string
	Link    string
}

DebugMessage is one debug message in "__debug__" of graph API response.

type DebugMode added in v1.5.0 

type DebugMode string

Graph API debug mode. See https://developers.facebook.com/docs/graph-api/using-graph-api/v2.3#graphapidebugmode 

const (
	DEBUG_OFF DebugMode = "" // turn off debug.

	DEBUG_ALL     DebugMode = "all"
	DEBUG_INFO    DebugMode = "info"
	DEBUG_WARNING DebugMode = "warning"
)

Graph API debug mode values.

type Error 

type Error struct {
	Message      string
	Type         string
	Code         int
	ErrorSubcode int // subcode for authentication related errors.
}

Facebook API error.

func (*Error) Error 

func (e *Error) Error() string

Returns error string.

type Float32 

type Float32 float32

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type Float64 

type Float64 float64

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type HttpClient 

type HttpClient interface {
	Do(req *http.Request) (resp *http.Response, err error)
	Get(url string) (resp *http.Response, err error)
	Post(url string, bodyType string, body io.Reader) (resp *http.Response, err error)
}

An interface to send http request. This interface is designed to be compatible with type `*http.Client`.

func DefaultHttpClient added in v1.5.0 

func DefaultHttpClient() HttpClient

DefaultHttpClient returns the http client for default session.

type Int 

type Int int

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type Int16 

type Int16 int16

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type Int32 

type Int32 int32

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type Int64 

type Int64 int64

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type Int8 

type Int8 int8

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type Method 

type Method string

API HTTP method. Can be GET, POST or DELETE. 

const (
	GET    Method = "GET"
	POST   Method = "POST"
	DELETE Method = "DELETE"
	PUT    Method = "PUT"
)

Facebook graph api methods.

type PagingResult 

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

Represents facebook API call result with paging information.

func (*PagingResult) Data 

func (pr *PagingResult) Data() []Result

Get current data.

func (*PagingResult) Decode added in v1.2.0 

func (pr *PagingResult) Decode(v interface{}) (err error)

Decodes the current full result to a struct. See Result#Decode.

func (*PagingResult) HasNext 

func (pr *PagingResult) HasNext() bool

Check whether there is next page.

func (*PagingResult) HasPrevious 

func (pr *PagingResult) HasPrevious() bool

Check whether there is previous page.

func (*PagingResult) Next 

func (pr *PagingResult) Next() (noMore bool, err error)

Read next page.

func (*PagingResult) Previous 

func (pr *PagingResult) Previous() (noMore bool, err error)

Read previous page.

type Params 

type Params map[string]interface{}

API params.

For general uses, just use Params as an ordinary map.

For advanced uses, use MakeParams to create Params from any struct.

func MakeParams 

func MakeParams(data interface{}) (params Params)

Makes a new Params instance by given data. Data must be a struct or a map with string keys. MakeParams will change all struct field name to lower case name with underscore. e.g. "FooBar" will be changed to "foo_bar".

Returns nil if data cannot be used to make a Params instance.

func (Params) Encode 

func (params Params) Encode(writer io.Writer) (mime string, err error)

Encodes params to query string. If map value is not a string, Encode uses json.Marshal() to convert value to string.

Encode will panic if Params contains values that cannot be marshalled to json string.

type Result 

type Result map[string]interface{}

Facebook API call result.

func Api 

func Api(path string, method Method, params Params) (Result, error)

Makes a facebook graph api call with default session.

Method can be GET, POST, DELETE or PUT.

Params represents query strings in this call. Keys and values in params will be encoded into the URL automatically, so there is no need to encode keys or values in params manually. Params can be nil.

If you want to get 

https://graph.facebook.com/huandu?fields=name,username

Api should be called as following 

Api("/huandu", GET, Params{"fields": "name,username"})

or in a simplified way 

Get("/huandu", Params{"fields": "name,username"})

Api is a wrapper of Session.Api(). It's designed for graph api that doesn't require app id, app secret and access token. It can be called in multiple goroutines.

If app id, app secret or access token is required in graph api, caller should create a new facebook session through App instance instead.

func Batch 

func Batch(batchParams Params, params ...Params) ([]Result, error)

Makes a batch facebook graph api call with default session. Batch is designed for more advanced usage including uploading binary files.

An uploading files sample 

// equivalent to following curl command (borrowed from facebook docs)
//     curl \
//         -F 'access_token=…' \
//         -F 'batch=[{"method":"POST","relative_url":"me/photos","body":"message=My cat photo","attached_files":"file1"},{"method":"POST","relative_url":"me/photos","body":"message=My dog photo","attached_files":"file2"},]' \
//         -F 'file1=@cat.gif' \
//         -F 'file2=@dog.jpg' \
//         https://graph.facebook.com
Batch(Params{
    "access_token": "the-access-token",
    "file1": File("cat.gif"),
    "file2": File("dog.jpg"),
}, Params{
    "method": "POST",
    "relative_url": "me/photos",
    "body": "message=My cat photo",
    "attached_files": "file1",
}, Params{
    "method": "POST",
    "relative_url": "me/photos",
    "body": "message=My dog photo",
    "attached_files": "file2",
})

Facebook document: https://developers.facebook.com/docs/graph-api/making-multiple-requests

func BatchApi 

func BatchApi(accessToken string, params ...Params) ([]Result, error)

Makes a batch facebook graph api call with default session.

BatchApi supports most kinds of batch calls defines in facebook batch api document, except uploading binary data. Use Batch to do so.

Note: API response is stored in "body" field of a Result. 

results, _ := BatchApi(accessToken, Params{...}, Params{...})

// Use first batch api response.
var res1 *BatchResult
var err error
res1, err = results[0].Batch()

if err != nil {
    // this is not a valid batch api response.
}

// Use BatchResult#Result to get response body content as Result.
res := res1.Result

Facebook document: https://developers.facebook.com/docs/graph-api/making-multiple-requests

func Delete 

func Delete(path string, params Params) (Result, error)

Delete is a short hand of Api(path, DELETE, params).

func Get 

func Get(path string, params Params) (Result, error)

Get is a short hand of Api(path, GET, params).

func MakeResult 

func MakeResult(jsonBytes []byte) (Result, error)

MakeResult makes a Result from facebook Graph API response.

func Post 

func Post(path string, params Params) (Result, error)

Post is a short hand of Api(path, POST, params).

func Put 

func Put(path string, params Params) (Result, error)

Put is a short hand of Api(path, PUT, params).

func Request 

func Request(request *http.Request) (Result, error)

Makes an arbitrary HTTP request with default session. It expects server responses a facebook Graph API response. 

request, _ := http.NewRequest("https://graph.facebook.com/538744468", "GET", nil)
res, err := Request(request)
fmt.Println(res["gender"])  // get "male"

func (Result) Batch added in v1.3.0 

func (res Result) Batch() (*BatchResult, error)

Batch creates a BatchResult for this result and returns error if the Result is not a batch api response.

See BatchApi document for a sample usage.

func (Result) DebugInfo added in v1.5.0 

func (res Result) DebugInfo() *DebugInfo

DebugInfo creates a DebugInfo for this result if this result has "__debug__" key.

func (Result) Decode 

func (res Result) Decode(v interface{}) (err error)

Decode decodes full result to a struct. It only decodes fields defined in the struct.

As all facebook response fields are lower case strings, Decode will convert all camel-case field names to lower case string. e.g. field name "FooBar" will be converted to "foo_bar". The side effect is that if a struct has 2 fields with only capital differences, decoder will map these fields to a same result value.

If a field is missing in the result, Decode keeps it unchanged by default.

The decoding of each struct field can be customized by the format string stored under the "facebook" key or the "json" key in the struct field's tag. The "facebook" key is recommended as it's specifically designed for this package.

Examples: 

type Foo struct {
    // "id" must exist in response. note the leading comma.
    Id string `facebook:",required"`

    // use "name" as field name in response.
    TheName string `facebook:"name"`

    // the "json" key also works as expected.
    Key string `json:"my_key"`

    // if both "facebook" and "json" key are set, the "facebook" key is used.
    Value string `facebook:"value" json:"shadowed"`
}

To change default behavior, set a struct tag `facebook:",required"` to fields should not be missing.

Returns error if v is not a struct or any required v field name absents in res.

func (Result) DecodeField 

func (res Result) DecodeField(field string, v interface{}) error

DecodeField decodes a field of result to any type, including struct. Field name format is defined in Result.Get().

More details about decoding struct see Result.Decode().

func (Result) Err 

func (res Result) Err() error

Err returns an error if Result is a Graph API error.

The returned error can be converted to Error by type assertion. 

err := res.Err()
if err != nil {
    if e, ok := err.(*Error); ok {
        // read more details in e.Message, e.Code and e.Type
    }
}

For more information about Graph API Errors, see https://developers.facebook.com/docs/reference/api/errors/

func (Result) Get 

func (res Result) Get(field string) interface{}

Get gets a field from Result.

Field can be a dot separated string. If field name is "a.b.c", it will try to return value of res["a"]["b"]["c"].

To access array items, use index value in field. For instance, field "a.0.c" means to read res["a"][0]["c"].

It doesn't work with Result which has a key contains dot. Use GetField in this case.

Returns nil if field doesn't exist.

func (Result) GetField 

func (res Result) GetField(fields ...string) interface{}

GetField gets a field from Result.

Arguments are treated as keys to access value in Result. If arguments are "a","b","c", it will try to return value of res["a"]["b"]["c"].

To access array items, use index value as a string. For instance, args of "a", "0", "c" means to read res["a"][0]["c"].

Returns nil if field doesn't exist.

func (Result) Paging 

func (res Result) Paging(session *Session) (*PagingResult, error)

Paging creates a PagingResult for this Result and returns error if the Result cannot be used for paging.

Facebook uses following JSON structure to response paging information. If "data" doesn't present in Result, Paging will return error. 

{
    "data": [...],
    "paging": {
        "previous": "https://graph.facebook.com/...",
        "next": "https://graph.facebook.com/..."
    }
}

type Session 

type Session struct {
	HttpClient HttpClient
	Version    string // facebook versioning.
	// contains filtered or unexported fields
}

Holds a facebook session with an access token. Session should be created by App.Session or App.SessionFromSignedRequest.

func (*Session) AccessToken 

func (session *Session) AccessToken() string

Gets current access token.

func (*Session) Api 

func (session *Session) Api(path string, method Method, params Params) (Result, error)

Makes a facebook graph api call.

If session access token is set, "access_token" in params will be set to the token value.

Returns facebook graph api call result. If facebook returns error in response, returns error details in res and set err.

func (*Session) App 

func (session *Session) App() *App

Gets associated App.

func (*Session) AppsecretProof 

func (session *Session) AppsecretProof() string

Check appsecret proof is enabled or not.

func (*Session) Batch 

func (session *Session) Batch(batchParams Params, params ...Params) ([]Result, error)

Makes a batch facebook graph api call. Batch is designed for more advanced usage including uploading binary files.

If session access token is set, "access_token" in batchParams will be set to the token value.

Facebook document: https://developers.facebook.com/docs/graph-api/making-multiple-requests

func (*Session) BatchApi 

func (session *Session) BatchApi(params ...Params) ([]Result, error)

Makes a batch call. Each params represent a single facebook graph api call.

BatchApi supports most kinds of batch calls defines in facebook batch api document, except uploading binary data. Use Batch to upload binary data.

If session access token is set, the token will be used in batch api call.

Returns an array of batch call result on success.

Facebook document: https://developers.facebook.com/docs/graph-api/making-multiple-requests

func (*Session) Context 

func (session *Session) Context() context.Context

Context returns the session's context. To change the context, use `Session#WithContext`.

The returned context is always non-nil; it defaults to the background context. For outgoing Facebook API requests, the context controls timeout/deadline and cancelation.

func (*Session) Debug added in v1.5.0 

func (session *Session) Debug() DebugMode

Debug returns current debug mode.

func (*Session) Delete 

func (session *Session) Delete(path string, params Params) (Result, error)

Delete is a short hand of Api(path, DELETE, params).

func (*Session) EnableAppsecretProof 

func (session *Session) EnableAppsecretProof(enabled bool) error

Enable or disable appsecret proof status. Returns error if there is no App associated with this Session.

func (*Session) Get 

func (session *Session) Get(path string, params Params) (Result, error)

Get is a short hand of Api(path, GET, params).

func (*Session) Inspect 

func (session *Session) Inspect() (result Result, err error)

Inspect Session access token. Returns JSON array containing data about the inspected token. See https://developers.facebook.com/docs/facebook-login/manually-build-a-login-flow/v2.2#checktoken

func (*Session) Post 

func (session *Session) Post(path string, params Params) (Result, error)

Post is a short hand of Api(path, POST, params).

func (*Session) Put 

func (session *Session) Put(path string, params Params) (Result, error)

Put is a short hand of Api(path, PUT, params).

func (*Session) Request 

func (session *Session) Request(request *http.Request) (res Result, err error)

Makes an arbitrary HTTP request. It expects server responses a facebook Graph API response. 

request, _ := http.NewRequest("https://graph.facebook.com/538744468", "GET", nil)
res, err := session.Request(request)
fmt.Println(res["gender"])  // get "male"

func (*Session) SetAccessToken 

func (session *Session) SetAccessToken(token string)

Sets a new access token.

func (*Session) SetDebug added in v1.5.0 

func (session *Session) SetDebug(debug DebugMode) DebugMode

SetDebug updates per session debug mode and returns old mode. If per session debug mode is DEBUG_OFF, session will use global Debug mode.

func (*Session) User 

func (session *Session) User() (id string, err error)

Gets current user id from access token.

Returns error if access token is not set or invalid.

It's a standard way to validate a facebook access token.

func (*Session) Validate 

func (session *Session) Validate() (err error)

Validates Session access token. Returns nil if access token is valid.

func (*Session) WithContext 

func (session *Session) WithContext(ctx context.Context) *Session

WithContext returns a shallow copy of session with its context changed to ctx. The provided ctx must be non-nil.

type Uint 

type Uint uint

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type Uint16 

type Uint16 uint16

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type Uint32 

type Uint32 uint32

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type Uint64 

type Uint64 uint64

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

type Uint8 

type Uint8 uint8

Special number types which can be decoded from either a number or a string. If developers intend to use a string in JSON as a number, these types can parse string to a number implicitly in `Result#Decode` or `Result#DecodeField`.

Caveats: Parsing a string to a number may lose accuracy or shadow some errors.

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