Utility for printing JWT

.gitignore

@@ -11,5 +11,8 @@
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
 
+# Environment variable files
+**/.env
+
 # Dependency directories (remove the comment below to include it)
 # vendor/

cmd/print-jwt/main.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/nicheinc/sfdcclient/v2"
+	"github.com/peterbourgon/ff/v3"
+)
+
+func main() {
+
+	var (
+		sandbox              bool
+		salesforceInstanceID string
+		privateKeyFile       string
+		consumerKey          string
+		username             string
+	)
+
+	flag.BoolVar(&sandbox, "sandbox", false, "Whether the instance the client connects to, is a sandbox or not")
+	flag.StringVar(&salesforceInstanceID, "salesforce.instanceID", "", "Salesforce instance URL")
+	flag.StringVar(&privateKeyFile, "salesforce.app.cert.privateKey", "", "Path to the private key file")
+	flag.StringVar(&consumerKey, "salesforce.app.consumerKey", "", "Connected app consumer key")
+	flag.StringVar(&username, "salesforce.app.username", "", "Username using the connected app")
+
+	if err := ff.Parse(flag.CommandLine, os.Args[1:], ff.WithEnvVarNoPrefix()); err != nil {
+		log.Fatalf("Error parsing flags: %s", err)
+	}
+
+	// Read your private key into memory
+	privateKeyBytes, err := os.ReadFile(privateKeyFile)
+	if err != nil {
+		log.Fatalf("Error reading private key: %s", err)
+	}
+
+	client, err := sfdcclient.NewClientWithJWTBearer(
+		sandbox,              // whether the instance the client connects to, is a sandbox or not
+		salesforceInstanceID, // the salesforce instance URL
+		consumerKey,          // the connected app consumer key
+		username,             // the username using the connected app
+		privateKeyBytes,
+		3*time.Second, // request timeout for the OAuth new token HTTP request (3 minute max)
+		http.Client{ // underlying HTTP client making all HTTP calls
+			Timeout: 5 * time.Second,
+		},
+	)
+	if err != nil {
+		log.Fatalf("Error initializing connected app salesforce client: %s", err)
+	}
+
+	jwt, err := client.JWT()
+	if err != nil {
+		log.Fatalf("Error getting JWT: %s", err)
+	}
+	fmt.Printf("%s\n", jwt)
+}

go.mod

@@ -1,5 +1,8 @@
-module github.com/nicheinc/sfdcclient
+module github.com/nicheinc/sfdcclient/v2
 
-go 1.15
+go 1.18
 
-require github.com/dgrijalva/jwt-go v3.2.0+incompatible
+require (
+	github.com/dgrijalva/jwt-go v3.2.0+incompatible
+	github.com/peterbourgon/ff/v3 v3.4.0
+)

go.sum

@@ -1,2 +1,4 @@
 github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumCAMpl/TFQ4/5kLM=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
+github.com/peterbourgon/ff/v3 v3.4.0 h1:QBvM/rizZM1cB0p0lGMdmR7HxZeI/ZrBWB4DqLkMUBc=
+github.com/peterbourgon/ff/v3 v3.4.0/go.mod h1:zjJVUhx+twciwfDl0zBcFzl4dW8axCRyXE/eKY9RztQ=

jwtBearer.go

@@ -39,7 +39,7 @@ type jwtBearer struct {
 	errMutex *sync.RWMutex
 }
 
-func NewClientWithJWTBearer(sandbox bool, instanceURL, consumerKey, username string, privateKey []byte, tokenDuration time.Duration, httpClient http.Client) (Client, error) {
+func NewClientWithJWTBearer(sandbox bool, instanceURL, consumerKey, username string, privateKey []byte, tokenDuration time.Duration, httpClient http.Client) (*jwtBearer, error) {
 	jwtBearer := jwtBearer{
 		client:           httpClient,
 		instanceURL:      instanceURL,
@@ -78,17 +78,7 @@ func (c *jwtBearer) newAccessToken() error {
 		c.setErr(err)
 	}()
 	// Create JWT
-	token := jwt.NewWithClaims(
-		jwt.SigningMethodRS256,
-		jwt.StandardClaims{
-			Issuer:    c.consumerKey,
-			Audience:  c.authServerURL,
-			Subject:   c.username,
-			ExpiresAt: time.Now().Add(c.tokenDuration).UTC().Unix(),
-		},
-	)
-	// Sign JWT with the private key
-	signedJWT, err := token.SignedString(c.rsaPrivateKey)
+	signedJWT, err := c.JWT()
 	if err != nil {
 		return err
 	}
@@ -142,6 +132,21 @@ func (c *jwtBearer) newAccessToken() error {
 	return nil
 }
 
+func (c *jwtBearer) JWT() (string, error) {
+	// Create JWT
+	token := jwt.NewWithClaims(
+		jwt.SigningMethodRS256,
+		jwt.StandardClaims{
+			Issuer:    c.consumerKey,
+			Audience:  c.authServerURL,
+			Subject:   c.username,
+			ExpiresAt: time.Now().Add(c.tokenDuration).UTC().Unix(),
+		},
+	)
+	// Sign JWT with the private key
+	return token.SignedString(c.rsaPrivateKey)
+}
+
 func (c jwtBearer) checkErr() error {
 	c.errMutex.RLock()
 	defer c.errMutex.RUnlock()