feat: add graceful shutdown, health endpoint, and improved client API

client/client.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"os"
 	"strings"
 )
 
@@ -17,23 +18,38 @@ const (
 
 // Client is a pastebin API client.
 type Client struct {
-	url      string
-	insecure bool
+	serviceURL string
+	insecure   bool
+	output     io.Writer
 }
 
 // NewClient creates a new pastebin Client.
 // When insecure is true, TLS certificate verification is skipped.
+// Output is written to stdout by default; use WithOutput to change.
 func NewClient(serviceURL string, insecure bool) *Client {
-	return &Client{url: serviceURL, insecure: insecure}
+	return &Client{serviceURL: serviceURL, insecure: insecure, output: os.Stdout}
+}
+
+// WithOutput sets the writer where paste URLs are printed.
+// Returns the Client for chaining.
+func (client *Client) WithOutput(writer io.Writer) *Client {
+	client.output = writer
+	return client
 }
 
 // Paste reads from body and submits it as a new paste.
-// It prints the resulting paste URL to stdout.
-func (c *Client) Paste(body io.Reader) error {
+// It prints the resulting paste URL to the configured output writer.
+func (client *Client) Paste(body io.Reader) error {
 	transport := &http.Transport{
-		TLSClientConfig: &tls.Config{InsecureSkipVerify: c.insecure}, //nolint:gosec // user-requested skip
+		TLSClientConfig: &tls.Config{InsecureSkipVerify: client.insecure}, //nolint:gosec // user-requested skip
+	}
+	httpClient := &http.Client{
+		Transport: transport,
+		// Don't follow redirects; capture the URL from the response.
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
 	}
-	httpClient := &http.Client{Transport: transport}
 
 	var builder strings.Builder
 	if _, err := io.Copy(&builder, body); err != nil {
@@ -43,16 +59,30 @@ func (c *Client) Paste(body io.Reader) error {
 	formValues := url.Values{}
 	formValues.Set(formFieldBlob, builder.String())
 
-	resp, err := httpClient.PostForm(c.url, formValues)
+	resp, err := httpClient.PostForm(client.serviceURL, formValues)
 	if err != nil {
-		return fmt.Errorf("posting paste to %s: %w", c.url, err)
+		return fmt.Errorf("posting paste to %s: %w", client.serviceURL, err)
 	}
 	defer resp.Body.Close()
 
-	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusMovedPermanently {
-		return fmt.Errorf("unexpected response from %s: %d", c.url, resp.StatusCode)
+	switch resp.StatusCode {
+	case http.StatusOK:
+		// Plain text response contains the paste URL in the body.
+		responseBody, readErr := io.ReadAll(resp.Body)
+		if readErr != nil {
+			return fmt.Errorf("reading response body: %w", readErr)
+		}
+		fmt.Fprint(client.output, string(responseBody))
+		return nil
+	case http.StatusFound, http.StatusMovedPermanently:
+		// HTML response redirects to the paste URL.
+		location := resp.Header.Get("Location")
+		if location == "" {
+			return fmt.Errorf("redirect response missing Location header")
+		}
+		fmt.Fprint(client.output, location)
+		return nil
+	default:
+		return fmt.Errorf("unexpected response from %s: %d", client.serviceURL, resp.StatusCode)
 	}
-
-	fmt.Print(resp.Request.URL.String())
-	return nil
 }