go-lemmy/lemmy.go
2023-04-20 19:27:38 -07:00

179 lines
3.7 KiB
Go

package lemmy
import (
"bytes"
"context"
"encoding/json"
"io"
"net/http"
"net/url"
"reflect"
"github.com/google/go-querystring/query"
"go.elara.ws/go-lemmy/types"
)
// Client is a client for Lemmy's HTTP API
type Client struct {
client *http.Client
baseURL *url.URL
Token string
}
// New creates a new Lemmy client with the default HTTP client.
func New(baseURL string) (*Client, error) {
return NewWithClient(baseURL, http.DefaultClient)
}
// NewWithClient creates a new Lemmy client with the given HTTP client
func NewWithClient(baseURL string, client *http.Client) (*Client, error) {
u, err := url.Parse(baseURL)
if err != nil {
return nil, err
}
u = u.JoinPath("/api/v3")
return &Client{baseURL: u, client: client}, nil
}
// ClientLogin logs in to Lemmy by sending an HTTP request to the
// login endpoint. It stores the returned token in the client
// for future use.
func (c *Client) ClientLogin(ctx context.Context, l types.Login) error {
lr, err := c.Login(ctx, l)
if err != nil {
return err
}
c.Token = lr.JWT.MustValue()
return nil
}
// req makes a request to the server
func (c *Client) req(ctx context.Context, method string, path string, data, resp any) (*http.Response, error) {
data = c.setAuth(data)
var r io.Reader
if data != nil {
jsonData, err := json.Marshal(data)
if err != nil {
return nil, err
}
r = bytes.NewReader(jsonData)
}
req, err := http.NewRequestWithContext(
ctx,
method,
c.baseURL.JoinPath(path).String(),
r,
)
if err != nil {
return nil, err
}
req.Header.Add("Content-Type", "application/json")
res, err := c.client.Do(req)
if err != nil {
return nil, err
}
defer res.Body.Close()
err = json.NewDecoder(res.Body).Decode(resp)
if err == io.EOF {
return res, nil
} else if err != nil {
return nil, err
}
return res, nil
}
// getReq makes a get request to the Lemmy server.
// It is separate from req() because it uses query
// parameters rather than a JSON request body.
func (c *Client) getReq(ctx context.Context, method string, path string, data, resp any) (*http.Response, error) {
data = c.setAuth(data)
getURL := c.baseURL.JoinPath(path)
vals, err := query.Values(data)
if err != nil {
return nil, err
}
getURL.RawQuery = vals.Encode()
req, err := http.NewRequestWithContext(
ctx,
method,
getURL.String(),
nil,
)
if err != nil {
return nil, err
}
res, err := c.client.Do(req)
if err != nil {
return nil, err
}
defer res.Body.Close()
err = json.NewDecoder(res.Body).Decode(resp)
if err == io.EOF {
return res, nil
} else if err != nil {
return nil, err
}
return res, nil
}
// resError returns an error if the given response is an error
func resError(res *http.Response, lr types.LemmyResponse) error {
if lr.Error.IsValid() {
return types.LemmyError{
Code: res.StatusCode,
ErrStr: lr.Error.MustValue(),
}
} else if res.StatusCode != http.StatusOK {
return types.HTTPError{
Code: res.StatusCode,
}
} else {
return nil
}
}
// setAuth uses reflection to automatically
// set struct fields called Auth of type
// string or types.Optional[string] to the
// authentication token, then returns the
// updated struct
func (c *Client) setAuth(data any) any {
if data == nil {
return data
}
val := reflect.New(reflect.TypeOf(data))
val.Elem().Set(reflect.ValueOf(data))
authField := val.Elem().FieldByName("Auth")
if !authField.IsValid() {
return data
}
switch authField.Type().String() {
case "string":
authField.SetString(c.Token)
case "types.Optional[string]":
setMtd := authField.MethodByName("Set")
out := setMtd.Call([]reflect.Value{reflect.ValueOf(c.Token)})
authField.Set(out[0])
default:
return data
}
return val.Elem().Interface()
}