Mail api for sending order confirmation to planetposen customers

client/http.go

@@ -0,0 +1,135 @@
+// Package client contains a HTTP client.
+package client
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"time"
+
+	opentracing "github.com/opentracing/opentracing-go"
+)
+
+// Parameters provides the parameters used when creating a new HTTP client.
+type Parameters struct {
+	Timeout *time.Duration
+}
+
+// NewHTTPClient instantiates a new HTTPClient based on provided parameters.
+func NewHTTPClient(parameters Parameters) HTTPClient {
+	if parameters.Timeout == nil {
+		timeout := 1 * time.Second
+		parameters.Timeout = &timeout
+	}
+
+	client := &http.Client{
+		Timeout: *parameters.Timeout,
+	}
+
+	return HTTPClient{client}
+}
+
+// HTTPRequestData contains the request data.
+type HTTPRequestData struct {
+	Method      string
+	URL         string
+	Headers     map[string]string
+	PostPayload []byte
+	GetPayload  *url.Values
+}
+
+// HTTPClient contains the HTTP client.
+type HTTPClient struct {
+	*http.Client
+}
+
+// HTTPStatusCodeError is an error that occurs when receiving an unexpected status code (>= 400).
+type HTTPStatusCodeError struct {
+	URL        string
+	StatusCode int
+	Message    string
+}
+
+// Error return an error string.
+func (e HTTPStatusCodeError) Error() string {
+	return fmt.Sprintf("Error response from %s, got status: %d", e.URL, e.StatusCode)
+}
+
+// RequestBytes does the actual HTTP request.
+// Returns a slice of bytes or an error.
+func (client *HTTPClient) RequestBytes(ctx context.Context, reqData HTTPRequestData) ([]byte, error) {
+	span, ctx := opentracing.StartSpanFromContext(ctx, "RequestBytes")
+	defer span.Finish()
+
+	r, err := client.request(ctx, reqData)
+
+	if err != nil {
+		return nil, err
+	}
+
+	defer r.Body.Close()
+
+	if r.StatusCode >= 400 {
+		resp, _ := ioutil.ReadAll(r.Body)
+		message := string(resp)
+		span.SetTag("error", true)
+		span.LogKV("message", fmt.Errorf("error making request to %s, got error: %s", reqData.URL, message))
+		return nil, HTTPStatusCodeError{
+			URL:        reqData.URL,
+			StatusCode: r.StatusCode,
+			Message:    message,
+		}
+	}
+
+	return ioutil.ReadAll(r.Body)
+}
+
+func (client *HTTPClient) request(ctx context.Context, reqData HTTPRequestData) (*http.Response, error) {
+	var req *http.Request
+	var err error
+
+	if reqData.Method == http.MethodPost {
+		req, err = http.NewRequest(reqData.Method, reqData.URL, bytes.NewBuffer(reqData.PostPayload))
+	} else {
+		req, err = http.NewRequest(reqData.Method, reqData.URL, nil)
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	if reqData.GetPayload != nil {
+		req.URL.RawQuery = reqData.GetPayload.Encode()
+	}
+
+	span := opentracing.SpanFromContext(ctx)
+
+	if span != nil {
+		opentracing.GlobalTracer().Inject(
+			span.Context(),
+			opentracing.HTTPHeaders,
+			opentracing.HTTPHeadersCarrier(req.Header),
+		)
+	}
+
+	for k, v := range reqData.Headers {
+		req.Header.Set(k, v)
+	}
+
+	req.Header.Set("User-Agent", "planetposen-mail")
+
+	resp, err := client.Do(req)
+
+	if err != nil {
+		if reqData.Method == http.MethodPost {
+			return resp, fmt.Errorf("Error making request: %v. Body: %s", err, reqData.PostPayload)
+		}
+
+		return resp, fmt.Errorf("Error making request: %v. Query: %v", err, req.URL.RawQuery)
+	}
+
+	return resp, nil
+}