mirage.go

// go-mirage-api
//
// Copyright 2023, Valerian Saliou
// Author: Valerian Saliou <valerian@valeriansaliou.name>

package mirage


import (
  "bytes"
  "encoding/json"
  "fmt"
  "time"
  "io"
  "errors"
  "io/ioutil"
  "net/http"
  "net/url"
)


const (
  libraryVersion = "1.10.1"
  defaultRestEndpointURL = "https://api.mirage-ai.com/v1/"
  userAgent = "go-mirage-api/" + libraryVersion
  acceptContentType = "application/json"
  clientTimeout = 40
  clientIdleConnTimeout = 45
  clientMaxIdleConns = 16
  clientMaxConnsPerHost = 64
  clientMaxIdleConnsPerHost = 4
)

var errorDoNilRequest = errors.New("request could not be constructed")

// ClientConfig mapping
type ClientConfig struct {
  HTTPClient *http.Client
  RestEndpointURL string
}

type auth struct {
  Username string
  Password string
}

// Client maps an API client
type Client struct {
  config *ClientConfig
  client *http.Client
  auth *auth

  BaseURL *url.URL
  UserAgent string

  common service

  Task *TaskService
  Data *DataService
}

type service struct {
  client *Client
}

// RequestContext maps custom context for a request
type RequestContext struct {
  Trace  string  `json:"string"`
}

// Response maps an API HTTP response
type Response struct {
  *http.Response
}

type errorResponse struct {
  Response *http.Response
  Reason   string  `json:"reason,omitempty"`
  Message  string  `json:"message,omitempty"`
}


// Error prints an error response
func (response *errorResponse) Error() string {
  return fmt.Sprintf("%v %v: %d %v",
    response.Response.Request.Method, response.Response.Request.URL,
    response.Response.StatusCode, response.Reason)
}


// NewWithConfig returns a new API client
func NewWithConfig(userID string, secretKey string, config ClientConfig) *Client {
  // Defaults
  if config.HTTPClient == nil {
    // Build client transport
    clientTransport := http.DefaultTransport.(*http.Transport).Clone()
    clientTransport.IdleConnTimeout = time.Duration(clientIdleConnTimeout * time.Second)
    clientTransport.MaxIdleConns = clientMaxIdleConns
    clientTransport.MaxConnsPerHost = clientMaxConnsPerHost
    clientTransport.MaxIdleConnsPerHost = clientMaxIdleConnsPerHost

    // Create client
    config.HTTPClient = &http.Client{
      Timeout: time.Duration(clientTimeout * time.Second),
      Transport: clientTransport,
    }
  }
  if config.RestEndpointURL == "" {
    config.RestEndpointURL = defaultRestEndpointURL
  }

  // Create client
  baseURL, _ := url.Parse(config.RestEndpointURL)

  client := &Client{config: &config, client: config.HTTPClient, auth: &auth{userID, secretKey}, BaseURL: baseURL, UserAgent: userAgent}
  client.common.client = client

  // Map services
  client.Task = (*TaskService)(&client.common)
  client.Data = (*DataService)(&client.common)

  return client
}


// New returns a new API client
func New(userID string, secretKey string) *Client {
  return NewWithConfig(userID, secretKey, ClientConfig{})
}


// NewRequest creates an API request
func (client *Client) NewRequest(method, urlStr string, body interface{}, ctx RequestContext) (*http.Request, error) {
  rel, err := url.Parse(urlStr)
  if err != nil {
    return nil, err
  }

  url := client.BaseURL.ResolveReference(rel)

  var buf io.ReadWriter
  if body != nil {
    buf = new(bytes.Buffer)
    err := json.NewEncoder(buf).Encode(body)
    if err != nil {
      return nil, err
    }
  }

  req, err := http.NewRequest(method, url.String(), buf)
  if err != nil {
    return nil, err
  }

  req.SetBasicAuth(client.auth.Username, client.auth.Password)

  req.Header.Add("Accept", acceptContentType)
  req.Header.Add("Content-Type", acceptContentType)

  if client.UserAgent != "" {
    req.Header.Add("User-Agent", client.UserAgent)
  }

  if ctx.Trace != "" {
    // Stamp request with provided trace identifier (this is optional, but \
    //   can be used to track request flows across Mirage backend systems, for \
    //   debugging purposes)
    req.Header.Add("X-Request-ID", ctx.Trace)
  }

  return req, nil
}


// Do sends an API request
func (client *Client) Do(req *http.Request, v interface{}) (*Response, error) {
  if req == nil {
    return nil, errorDoNilRequest
  }

  resp, err := client.client.Do(req)
  if err != nil {
    return nil, err
  }

  defer func() {
    io.CopyN(ioutil.Discard, resp.Body, 512)
    resp.Body.Close()
  }()

  response := newResponse(resp)

  err = checkResponse(resp)
  if err != nil {
    return response, err
  }

  if v != nil {
    if w, ok := v.(io.Writer); ok {
      io.Copy(w, resp.Body)
    } else {
      err = json.NewDecoder(resp.Body).Decode(v)
      if err == io.EOF {
        err = nil
      }
    }
  }

  return response, err
}


// newResponse creates an HTTP response
func newResponse(httpResponse *http.Response) *Response {
  response := &Response{Response: httpResponse}

  return response
}


// checkResponse checks response for errors
func checkResponse(response *http.Response) error {
  // No error in response? (HTTP 2xx)
  if code := response.StatusCode; 200 <= code && code <= 299 {
    return nil
  }

  // Map response error data (eg. HTTP 4xx)
  errorResponse := &errorResponse{Response: response}

  data, err := ioutil.ReadAll(response.Body)
  if err == nil && data != nil {
    json.Unmarshal(data, errorResponse)
  }

  return errorResponse
}