Initial commit

1 files changed, 388 insertions, 0 deletions

diff --git a/mastodon/mastodon.go b/mastodon/mastodon.go
new file mode 100644
index 0000000..ff86d2b
--- /dev/null
+++ b/mastodon/mastodon.go
@@ -0,0 +1,388 @@
+// Package mastodon provides functions and structs for accessing the mastodon API.
+package mastodon
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"mime/multipart"
+	"net/http"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/tomnomnom/linkheader"
+)
+
+// Config is a setting for access mastodon APIs.
+type Config struct {
+	Server       string
+	ClientID     string
+	ClientSecret string
+	AccessToken  string
+}
+
+// Client is a API client for mastodon.
+type Client struct {
+	http.Client
+	config *Config
+}
+
+func (c *Client) doAPI(ctx context.Context, method string, uri string, params interface{}, res interface{}, pg *Pagination) error {
+	u, err := url.Parse(c.config.Server)
+	if err != nil {
+		return err
+	}
+	u.Path = path.Join(u.Path, uri)
+
+	var req *http.Request
+	ct := "application/x-www-form-urlencoded"
+	if values, ok := params.(url.Values); ok {
+		var body io.Reader
+		if method == http.MethodGet {
+			if pg != nil {
+				values = pg.setValues(values)
+			}
+			u.RawQuery = values.Encode()
+		} else {
+			body = strings.NewReader(values.Encode())
+		}
+		req, err = http.NewRequest(method, u.String(), body)
+		if err != nil {
+			return err
+		}
+	} else if file, ok := params.(string); ok {
+		f, err := os.Open(file)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+
+		var buf bytes.Buffer
+		mw := multipart.NewWriter(&buf)
+		part, err := mw.CreateFormFile("file", filepath.Base(file))
+		if err != nil {
+			return err
+		}
+		_, err = io.Copy(part, f)
+		if err != nil {
+			return err
+		}
+		err = mw.Close()
+		if err != nil {
+			return err
+		}
+		req, err = http.NewRequest(method, u.String(), &buf)
+		if err != nil {
+			return err
+		}
+		ct = mw.FormDataContentType()
+	} else if reader, ok := params.(io.Reader); ok {
+		var buf bytes.Buffer
+		mw := multipart.NewWriter(&buf)
+		part, err := mw.CreateFormFile("file", "upload")
+		if err != nil {
+			return err
+		}
+		_, err = io.Copy(part, reader)
+		if err != nil {
+			return err
+		}
+		err = mw.Close()
+		if err != nil {
+			return err
+		}
+		req, err = http.NewRequest(method, u.String(), &buf)
+		if err != nil {
+			return err
+		}
+		ct = mw.FormDataContentType()
+	} else {
+		if method == http.MethodGet && pg != nil {
+			u.RawQuery = pg.toValues().Encode()
+		}
+		req, err = http.NewRequest(method, u.String(), nil)
+		if err != nil {
+			return err
+		}
+	}
+	req = req.WithContext(ctx)
+	req.Header.Set("Authorization", "Bearer "+c.config.AccessToken)
+	if params != nil {
+		req.Header.Set("Content-Type", ct)
+	}
+
+	var resp *http.Response
+	backoff := 1000 * time.Millisecond
+	for {
+		resp, err = c.Do(req)
+		if err != nil {
+			return err
+		}
+		defer resp.Body.Close()
+
+		// handle status code 429, which indicates the server is throttling
+		// our requests. Do an exponential backoff and retry the request.
+		if resp.StatusCode == 429 {
+			if backoff > time.Hour {
+				break
+			}
+			backoff *= 2
+
+			select {
+			case <-time.After(backoff):
+			case <-ctx.Done():
+				return ctx.Err()
+			}
+			continue
+		}
+		break
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return parseAPIError("bad request", resp)
+	} else if res == nil {
+		return nil
+	} else if pg != nil {
+		if lh := resp.Header.Get("Link"); lh != "" {
+			pg2, err := newPagination(lh)
+			if err != nil {
+				return err
+			}
+			*pg = *pg2
+		}
+	}
+	return json.NewDecoder(resp.Body).Decode(&res)
+}
+
+// NewClient return new mastodon API client.
+func NewClient(config *Config) *Client {
+	return &Client{
+		Client: *http.DefaultClient,
+		config: config,
+	}
+}
+
+// Authenticate get access-token to the API.
+func (c *Client) Authenticate(ctx context.Context, username, password string) error {
+	params := url.Values{
+		"client_id":     {c.config.ClientID},
+		"client_secret": {c.config.ClientSecret},
+		"grant_type":    {"password"},
+		"username":      {username},
+		"password":      {password},
+		"scope":         {"read write follow"},
+	}
+
+	return c.authenticate(ctx, params)
+}
+
+// AuthenticateToken logs in using a grant token returned by Application.AuthURI.
+//
+// redirectURI should be the same as Application.RedirectURI.
+func (c *Client) AuthenticateToken(ctx context.Context, authCode, redirectURI string) error {
+	params := url.Values{
+		"client_id":     {c.config.ClientID},
+		"client_secret": {c.config.ClientSecret},
+		"grant_type":    {"authorization_code"},
+		"code":          {authCode},
+		"redirect_uri":  {redirectURI},
+	}
+
+	return c.authenticate(ctx, params)
+}
+
+func (c *Client) authenticate(ctx context.Context, params url.Values) error {
+	u, err := url.Parse(c.config.Server)
+	if err != nil {
+		return err
+	}
+	u.Path = path.Join(u.Path, "/oauth/token")
+
+	req, err := http.NewRequest(http.MethodPost, u.String(), strings.NewReader(params.Encode()))
+	if err != nil {
+		return err
+	}
+	req = req.WithContext(ctx)
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	resp, err := c.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return parseAPIError("bad authorization", resp)
+	}
+
+	var res struct {
+		AccessToken string `json:"access_token"`
+	}
+	err = json.NewDecoder(resp.Body).Decode(&res)
+	if err != nil {
+		return err
+	}
+	c.config.AccessToken = res.AccessToken
+	return nil
+}
+
+func (c *Client) GetAccessToken(ctx context.Context) string {
+	if c == nil || c.config == nil {
+		return ""
+	}
+	return c.config.AccessToken
+}
+
+// Toot is struct to post status.
+type Toot struct {
+	Status      string   `json:"status"`
+	InReplyToID string   `json:"in_reply_to_id"`
+	MediaIDs    []string `json:"media_ids"`
+	Sensitive   bool     `json:"sensitive"`
+	SpoilerText string   `json:"spoiler_text"`
+	Visibility  string   `json:"visibility"`
+}
+
+// Mention hold information for mention.
+type Mention struct {
+	URL      string `json:"url"`
+	Username string `json:"username"`
+	Acct     string `json:"acct"`
+	ID       string `json:"id"`
+}
+
+// Tag hold information for tag.
+type Tag struct {
+	Name    string    `json:"name"`
+	URL     string    `json:"url"`
+	History []History `json:"history"`
+}
+
+// History hold information for history.
+type History struct {
+	Day      string `json:"day"`
+	Uses     int64  `json:"uses"`
+	Accounts int64  `json:"accounts"`
+}
+
+// Attachment hold information for attachment.
+type Attachment struct {
+	ID          string         `json:"id"`
+	Type        string         `json:"type"`
+	URL         string         `json:"url"`
+	RemoteURL   string         `json:"remote_url"`
+	PreviewURL  string         `json:"preview_url"`
+	TextURL     string         `json:"text_url"`
+	Description string         `json:"description"`
+	Meta        AttachmentMeta `json:"meta"`
+}
+
+// AttachmentMeta holds information for attachment metadata.
+type AttachmentMeta struct {
+	Original AttachmentSize `json:"original"`
+	Small    AttachmentSize `json:"small"`
+}
+
+// AttachmentSize holds information for attatchment size.
+type AttachmentSize struct {
+	Width  int64   `json:"width"`
+	Height int64   `json:"height"`
+	Size   string  `json:"size"`
+	Aspect float64 `json:"aspect"`
+}
+
+// Emoji hold information for CustomEmoji.
+type Emoji struct {
+	ShortCode       string `json:"shortcode"`
+	StaticURL       string `json:"static_url"`
+	URL             string `json:"url"`
+	VisibleInPicker bool   `json:"visible_in_picker"`
+}
+
+// Results hold information for search result.
+type Results struct {
+	Accounts []*Account `json:"accounts"`
+	Statuses []*Status  `json:"statuses"`
+	Hashtags []string   `json:"hashtags"`
+}
+
+// Pagination is a struct for specifying the get range.
+type Pagination struct {
+	MaxID   string
+	SinceID string
+	MinID   string
+	Limit   int64
+}
+
+func newPagination(rawlink string) (*Pagination, error) {
+	if rawlink == "" {
+		return nil, errors.New("empty link header")
+	}
+
+	p := &Pagination{}
+	for _, link := range linkheader.Parse(rawlink) {
+		switch link.Rel {
+		case "next":
+			maxID, err := getPaginationID(link.URL, "max_id")
+			if err != nil {
+				return nil, err
+			}
+			p.MaxID = maxID
+		case "prev":
+			sinceID, err := getPaginationID(link.URL, "since_id")
+			if err != nil {
+				return nil, err
+			}
+			p.SinceID = sinceID
+
+			minID, err := getPaginationID(link.URL, "min_id")
+			if err != nil {
+				return nil, err
+			}
+			p.MinID = minID
+		}
+	}
+
+	return p, nil
+}
+
+func getPaginationID(rawurl, key string) (string, error) {
+	u, err := url.Parse(rawurl)
+	if err != nil {
+		return "", err
+	}
+
+	val := u.Query().Get(key)
+	if val == "" {
+		return "", nil
+	}
+
+	return string(val), nil
+}
+
+func (p *Pagination) toValues() url.Values {
+	return p.setValues(url.Values{})
+}
+
+func (p *Pagination) setValues(params url.Values) url.Values {
+	if p.MaxID != "" {
+		params.Set("max_id", string(p.MaxID))
+	}
+	if p.SinceID != "" {
+		params.Set("since_id", string(p.SinceID))
+	}
+	if p.MinID != "" {
+		params.Set("min_id", string(p.MinID))
+	}
+	if p.Limit > 0 {
+		params.Set("limit", fmt.Sprint(p.Limit))
+	}
+
+	return params
+}