From 816eeef808fdf5bd35d65402e988b9eaa733bc98 Mon Sep 17 00:00:00 2001
From: Steven Santos Erenst <stevenerenst@gmail.com>
Date: Sun, 15 Dec 2024 02:52:47 -0800
Subject: [PATCH] Add version to User-Agent header

Scryfall has requested that the version is included in the User-Agent
header. Lets do that to avoid future trouble. Also add the ability to
customize the User-Agent header.

Fixes #31
---
 CHANGELOG.md     |  6 ++++++
 scryfall.go      | 19 ++++++++++++++++---
 scryfall_test.go | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 69 insertions(+), 4 deletions(-)
 create mode 100644 CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..637267c
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,6 @@
+# Changelog
+
+## 0.6.0
+
+* Add version to User-Agent header
+* Add WithUserAgent option to enable customization of the User-Agent header
diff --git a/scryfall.go b/scryfall.go
index c24a0f0..07ce887 100644
--- a/scryfall.go
+++ b/scryfall.go
@@ -16,10 +16,12 @@ import (
 )
 
 const (
+	Version = "0.6.0"
+
 	defaultBaseURL      = "https://api.scryfall.com"
+	defaultUserAgent    = "go-scryfall/" + Version
 	defaultTimeout      = 30 * time.Second
 	defaultReqPerSecond = 10
-	userAgent           = "go-scryfall"
 
 	dateFormat      = "2006-01-02"
 	timestampFormat = "2006-01-02T15:04:05.999Z07:00"
@@ -111,6 +113,7 @@ func (e *Error) Error() string {
 
 type clientOptions struct {
 	baseURL      string
+	userAgent    string
 	clientSecret string
 	grantSecret  string
 	client       *http.Client
@@ -127,6 +130,13 @@ func WithBaseURL(baseURL string) ClientOption {
 	}
 }
 
+// WithUserAgent returns an option which overrides the default HTTP user agent.
+func WithUserAgent(userAgent string) ClientOption {
+	return func(o *clientOptions) {
+		o.userAgent = userAgent
+	}
+}
+
 // WithClientSecret returns an option which sets the client secret. The client
 // secret will configure the client to perform requests as the application
 // associated with the client secret.
@@ -163,6 +173,7 @@ func WithLimiter(limiter ratelimit.Limiter) ClientOption {
 // Client is a Scryfall API client.
 type Client struct {
 	baseURL       *url.URL
+	userAgent     string
 	authorization string
 
 	client  *http.Client
@@ -172,7 +183,8 @@ type Client struct {
 // NewClient returns a new Scryfall API client.
 func NewClient(options ...ClientOption) (*Client, error) {
 	co := &clientOptions{
-		baseURL: defaultBaseURL,
+		baseURL:   defaultBaseURL,
+		userAgent: defaultUserAgent,
 		client: &http.Client{
 			Timeout: defaultTimeout,
 		},
@@ -201,6 +213,7 @@ func NewClient(options ...ClientOption) (*Client, error) {
 
 	c := &Client{
 		baseURL:       baseURL,
+		userAgent:     co.userAgent,
 		authorization: authorization,
 		client:        co.client,
 		limiter:       co.limiter,
@@ -209,7 +222,7 @@ func NewClient(options ...ClientOption) (*Client, error) {
 }
 
 func (c *Client) doReq(ctx context.Context, req *http.Request, respBody interface{}) error {
-	req.Header.Set("User-Agent", userAgent)
+	req.Header.Set("User-Agent", c.userAgent)
 	if len(c.authorization) != 0 {
 		req.Header.Set("Authorization", c.authorization)
 	}
diff --git a/scryfall_test.go b/scryfall_test.go
index 94e9371..1d313f8 100644
--- a/scryfall_test.go
+++ b/scryfall_test.go
@@ -35,7 +35,6 @@ func setupTestServer(pattern string, handler func(http.ResponseWriter, *http.Req
 }
 
 func TestDateUnmarshalJSON(t *testing.T) {
-
 	tests := []struct {
 		in  []byte
 		out Date
@@ -186,6 +185,53 @@ func TestError(t *testing.T) {
 	}
 }
 
+func TestNewClientUserAgent(t *testing.T) {
+	tests := []struct {
+		name              string
+		clientOptions     []ClientOption
+		expectedUserAgent string
+	}{
+		{
+			name:              "default user agent",
+			clientOptions:     nil,
+			expectedUserAgent: defaultUserAgent,
+		},
+		{
+			name:              "custom user agent",
+			clientOptions:     []ClientOption{WithUserAgent("custom/1.2.3")},
+			expectedUserAgent: "custom/1.2.3",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(string(test.name), func(t *testing.T) {
+			handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				userAgent := r.Header.Get("User-Agent")
+				if userAgent != test.expectedUserAgent {
+					// I don't beleive they currently return an error for user agent
+					// issues but we want to make the test fail.
+					w.WriteHeader(http.StatusBadRequest)
+					fmt.Fprintln(w, `{"object": "error", "code": "bad_request", "status": 400, "details": ""}`)
+					return
+				}
+
+				fmt.Fprintln(w, `{"object": "list", "has_more": false, "data": []}`)
+			})
+			client, ts, err := setupTestServer("/symbology", handler, test.clientOptions...)
+			if err != nil {
+				t.Fatalf("Error setting up test server: %v", err)
+			}
+			defer ts.Close()
+
+			ctx := context.Background()
+			_, err = client.ListCardSymbols(ctx)
+			if err != nil {
+				t.Fatalf("Error validating user agent: %v", err)
+			}
+		})
+	}
+}
+
 func TestNewClientWithClientSecret(t *testing.T) {
 	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		authorizationHeader := r.Header.Get("Authorization")