hive.go

package thehive

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
)

const (
	libraryVersion = "0.1.0"

	// APIRoute represents a prefix path
	APIRoute = "api"

	userAgent = "go-thehive/" + libraryVersion
	mediaType = "application/json"
)

// Client is used to communicate with TheHive API
type Client struct {
	Client    *http.Client
	BaseURL   *url.URL
	UserAgent string
	Opts      *ClientOpts
	PageSize  int

	Cases CasesService
}

// ClientOpts represent options that are passed to client
type ClientOpts struct {
	Auth auth
}

// NewClient bootstraps a client to interact with TheHive API
func NewClient(baseurl string, opts *ClientOpts) (*Client, error) {
	u, err := url.Parse(baseurl)
	if err != nil {
		return nil, err
	}

	c := &Client{
		Client:    http.DefaultClient,
		BaseURL:   u,
		UserAgent: userAgent,
		Opts:      opts,
		PageSize:  100,
	}

	c.Cases = &CasesServiceOp{client: c}

	return c, nil
}

// NewRequest creates an API request. A relative URL can be provided in urlStr,
// in which case it is resolved relative to the BaseURL of the Client.
// Relative URLs should always be specified without a preceding slash. If
// specified, the value pointed to by body is JSON encoded and included as the
// request body.
func (c *Client) NewRequest(method, urlStr string, body interface{}) (*http.Request, error) {
	if !strings.HasSuffix(c.BaseURL.Path, "/") {
		return nil, fmt.Errorf("BaseURL must have a trailing slash, but %q does not", c.BaseURL)
	}
	u, err := c.BaseURL.Parse(urlStr)
	if err != nil {
		return nil, err
	}

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

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

	if body != nil {
		req.Header.Set("Content-Type", mediaType)
	}
	req.Header.Set("Accept", mediaType)
	if c.UserAgent != "" {
		req.Header.Set("User-Agent", c.UserAgent)
	}

	req.Header.Set("Authorization", c.Opts.Auth.Token())

	return req, nil
}

// Do sends an API request and returns the API response. The API response is
// JSON decoded and stored in the value pointed to by v, or returned as an
// error if an API error has occurred. If v implements the io.Writer
// interface, the raw response body will be written to v, without attempting to
// first decode it.
//
// The provided ctx must be non-nil. If it is canceled or times out,
// ctx.Err() will be returned.
func (c *Client) Do(ctx context.Context, req *http.Request, v interface{}) (*http.Response, error) {
	req = req.WithContext(ctx)

	resp, err := c.Client.Do(req)
	if err != nil {
		// If we got an error, and the context has been canceled,
		// the context's error is probably more useful.
		select {
		case <-ctx.Done():
			return nil, ctx.Err()
		default:
		}

		return nil, err
	}
	defer resp.Body.Close()

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

	if v != nil {
		if w, ok := v.(io.Writer); ok {
			io.Copy(w, resp.Body)
		} else {
			decErr := json.NewDecoder(resp.Body).Decode(v)
			if decErr == io.EOF {
				decErr = nil // ignore EOF errors caused by empty response body
			}
			if decErr != nil {
				err = decErr
			}
		}
	}

	return resp, err
}

func checkResponse(r *http.Response) error {
	switch r.StatusCode {
	case http.StatusOK:
		return nil
	case http.StatusUnauthorized:
		return errors.New("unauthorized")
	default:
		return fmt.Errorf("unknown error %s", r.Status)
	}
}