2 files changed, 234 insertions, 0 deletions
diff --git a/lib/common/error.go b/lib/common/error.go
new file mode 100644
index 0000000..d03c176
--- /dev/null
+++ b/lib/common/error.go
@@ -0,0 +1,13 @@
+package common
+
+import (
+	"github.com/gin-gonic/gin"
+)
+
+// APIError returns an uniform json formatted error
+func APIError(c *gin.Context, err string) {
+	c.JSON(500, gin.H{
+		"status": "error",
+		"error":  err,
+	})
+}
diff --git a/lib/common/httpclient.go b/lib/common/httpclient.go
new file mode 100644
index 0000000..40d7bc2
--- /dev/null
+++ b/lib/common/httpclient.go
@@ -0,0 +1,221 @@
+package common
+
+import (
+	"bytes"
+	"crypto/tls"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strings"
+)
+
+type HTTPClient struct {
+	httpClient http.Client
+	endpoint   string
+	apikey     string
+	username   string
+	password   string
+	id         string
+	csrf       string
+	conf       HTTPClientConfig
+}
+
+type HTTPClientConfig struct {
+	URLPrefix           string
+	HeaderAPIKeyName    string
+	Apikey              string
+	HeaderClientKeyName string
+	CsrfDisable         bool
+}
+
+// Inspired by syncthing/cmd/cli
+
+const insecure = false
+
+// HTTPNewClient creates a new HTTP client to deal with Syncthing
+func HTTPNewClient(baseURL string, cfg HTTPClientConfig) (*HTTPClient, error) {
+
+	// Create w new Http client
+	httpClient := http.Client{
+		Transport: &http.Transport{
+			TLSClientConfig: &tls.Config{
+				InsecureSkipVerify: insecure,
+			},
+		},
+	}
+	client := HTTPClient{
+		httpClient: httpClient,
+		endpoint:   baseURL,
+		apikey:     cfg.Apikey,
+		conf:       cfg,
+		/* TODO - add user + pwd support
+		username:   c.GlobalString("username"),
+		password:   c.GlobalString("password"),
+		*/
+	}
+
+	if client.apikey == "" {
+		if err := client.getCidAndCsrf(); err != nil {
+			return nil, err
+		}
+	}
+	return &client, nil
+}
+
+// Send request to retrieve Client id and/or CSRF token
+func (c *HTTPClient) getCidAndCsrf() error {
+	request, err := http.NewRequest("GET", c.endpoint, nil)
+	if err != nil {
+		return err
+	}
+	if _, err := c.handleRequest(request); err != nil {
+		return err
+	}
+	if c.id == "" {
+		return errors.New("Failed to get device ID")
+	}
+	if !c.conf.CsrfDisable && c.csrf == "" {
+		return errors.New("Failed to get CSRF token")
+	}
+	return nil
+}
+
+// GetClientID returns the id
+func (c *HTTPClient) GetClientID() string {
+	return c.id
+}
+
+// formatURL Build full url by concatenating all parts
+func (c *HTTPClient) formatURL(endURL string) string {
+	url := c.endpoint
+	if !strings.HasSuffix(url, "/") {
+		url += "/"
+	}
+	url += strings.TrimLeft(c.conf.URLPrefix, "/")
+	if !strings.HasSuffix(url, "/") {
+		url += "/"
+	}
+	return url + strings.TrimLeft(endURL, "/")
+}
+
+// HTTPGet Send a Get request to client and return an error object
+func (c *HTTPClient) HTTPGet(url string, data *[]byte) error {
+	_, err := c.HTTPGetWithRes(url, data)
+	return err
+}
+
+// HTTPGetWithRes Send a Get request to client and return both response and error
+func (c *HTTPClient) HTTPGetWithRes(url string, data *[]byte) (*http.Response, error) {
+	request, err := http.NewRequest("GET", c.formatURL(url), nil)
+	if err != nil {
+		return nil, err
+	}
+	res, err := c.handleRequest(request)
+	if err != nil {
+		return res, err
+	}
+	if res.StatusCode != 200 {
+		return res, errors.New(res.Status)
+	}
+
+	*data = c.responseToBArray(res)
+
+	return res, nil
+}
+
+// HTTPPost Send a POST request to client and return an error object
+func (c *HTTPClient) HTTPPost(url string, body string) error {
+	_, err := c.HTTPPostWithRes(url, body)
+	return err
+}
+
+// HTTPPostWithRes Send a POST request to client and return both response and error
+func (c *HTTPClient) HTTPPostWithRes(url string, body string) (*http.Response, error) {
+	request, err := http.NewRequest("POST", c.formatURL(url), bytes.NewBufferString(body))
+	if err != nil {
+		return nil, err
+	}
+	res, err := c.handleRequest(request)
+	if err != nil {
+		return res, err
+	}
+	if res.StatusCode != 200 {
+		return res, errors.New(res.Status)
+	}
+	return res, nil
+}
+
+func (c *HTTPClient) responseToBArray(response *http.Response) []byte {
+	defer response.Body.Close()
+	bytes, err := ioutil.ReadAll(response.Body)
+	if err != nil {
+		// TODO improved error reporting
+		fmt.Println("ERROR: " + err.Error())
+	}
+	return bytes
+}
+
+func (c *HTTPClient) handleRequest(request *http.Request) (*http.Response, error) {
+	if c.conf.HeaderAPIKeyName != "" && c.apikey != "" {
+		request.Header.Set(c.conf.HeaderAPIKeyName, c.apikey)
+	}
+	if c.conf.HeaderClientKeyName != "" && c.id != "" {
+		request.Header.Set(c.conf.HeaderClientKeyName, c.id)
+	}
+	if c.username != "" || c.password != "" {
+		request.SetBasicAuth(c.username, c.password)
+	}
+	if c.csrf != "" {
+		request.Header.Set("X-CSRF-Token-"+c.id[:5], c.csrf)
+	}
+
+	response, err := c.httpClient.Do(request)
+	if err != nil {
+		return nil, err
+	}
+
+	// Detect client ID change
+	cid := response.Header.Get(c.conf.HeaderClientKeyName)
+	if cid != "" && c.id != cid {
+		c.id = cid
+	}
+
+	// Detect CSR token change
+	for _, item := range response.Cookies() {
+		if item.Name == "CSRF-Token-"+c.id[:5] {
+			c.csrf = item.Value
+			goto csrffound
+		}
+	}
+	// OK CSRF found
+csrffound:
+
+	if response.StatusCode == 404 {
+		return nil, errors.New("Invalid endpoint or API call")
+	} else if response.StatusCode == 401 {
+		return nil, errors.New("Invalid username or password")
+	} else if response.StatusCode == 403 {
+		if c.apikey == "" {
+			// Request a new Csrf for next requests
+			c.getCidAndCsrf()
+			return nil, errors.New("Invalid CSRF token")
+		}
+		return nil, errors.New("Invalid API key")
+	} else if response.StatusCode != 200 {
+		data := make(map[string]interface{})
+		// Try to decode error field of APIError struct
+		json.Unmarshal(c.responseToBArray(response), &data)
+		if err, found := data["error"]; found {
+			return nil, fmt.Errorf(err.(string))
+		} else {
+			body := strings.TrimSpace(string(c.responseToBArray(response)))
+			if body != "" {
+				return nil, fmt.Errorf(body)
+			}
+		}
+		return nil, errors.New("Unknown HTTP status returned: " + response.Status)
+	}
+	return response, nil
+}