Implement HMAC-SHA256 signature generation and verification

This commit is contained in:
2026-01-08 03:02:09 -08:00
parent 2b0ccd6052
commit cc2c40bfbf
2 changed files with 434 additions and 0 deletions

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@@ -0,0 +1,295 @@
package imgcache
import (
"testing"
"time"
)
func TestSigner_Sign(t *testing.T) {
signer := NewSigner("test-secret-key")
req := &ImageRequest{
SourceHost: "cdn.example.com",
SourcePath: "/photos/cat.jpg",
SourceQuery: "",
Size: Size{Width: 800, Height: 600},
Format: FormatWebP,
Expires: time.Unix(1704067200, 0), // Fixed timestamp for reproducibility
}
sig1 := signer.Sign(req)
sig2 := signer.Sign(req)
// Same input should produce same signature
if sig1 != sig2 {
t.Errorf("Sign() produced different signatures for same input: %q vs %q", sig1, sig2)
}
// Signature should be non-empty
if sig1 == "" {
t.Error("Sign() produced empty signature")
}
// Different input should produce different signature
req2 := &ImageRequest{
SourceHost: "cdn.example.com",
SourcePath: "/photos/dog.jpg", // Different path
SourceQuery: "",
Size: Size{Width: 800, Height: 600},
Format: FormatWebP,
Expires: time.Unix(1704067200, 0),
}
sig3 := signer.Sign(req2)
if sig1 == sig3 {
t.Error("Sign() produced same signature for different input")
}
}
func TestSigner_Verify(t *testing.T) {
signer := NewSigner("test-secret-key")
tests := []struct {
name string
setup func() *ImageRequest
wantErr error
}{
{
name: "valid signature",
setup: func() *ImageRequest {
req := &ImageRequest{
SourceHost: "cdn.example.com",
SourcePath: "/photos/cat.jpg",
Size: Size{Width: 800, Height: 600},
Format: FormatWebP,
Expires: time.Now().Add(1 * time.Hour),
}
req.Signature = signer.Sign(req)
return req
},
wantErr: nil,
},
{
name: "expired signature",
setup: func() *ImageRequest {
req := &ImageRequest{
SourceHost: "cdn.example.com",
SourcePath: "/photos/cat.jpg",
Size: Size{Width: 800, Height: 600},
Format: FormatWebP,
Expires: time.Now().Add(-1 * time.Hour), // Expired
}
req.Signature = signer.Sign(req)
return req
},
wantErr: ErrSignatureExpired,
},
{
name: "invalid signature",
setup: func() *ImageRequest {
return &ImageRequest{
SourceHost: "cdn.example.com",
SourcePath: "/photos/cat.jpg",
Size: Size{Width: 800, Height: 600},
Format: FormatWebP,
Expires: time.Now().Add(1 * time.Hour),
Signature: "invalid-signature",
}
},
wantErr: ErrSignatureInvalid,
},
{
name: "missing expiration",
setup: func() *ImageRequest {
return &ImageRequest{
SourceHost: "cdn.example.com",
SourcePath: "/photos/cat.jpg",
Size: Size{Width: 800, Height: 600},
Format: FormatWebP,
Signature: "some-signature",
// Expires is zero
}
},
wantErr: ErrMissingExpiration,
},
{
name: "tampered request",
setup: func() *ImageRequest {
req := &ImageRequest{
SourceHost: "cdn.example.com",
SourcePath: "/photos/cat.jpg",
Size: Size{Width: 800, Height: 600},
Format: FormatWebP,
Expires: time.Now().Add(1 * time.Hour),
}
req.Signature = signer.Sign(req)
// Tamper with the request
req.SourcePath = "/photos/secret.jpg"
return req
},
wantErr: ErrSignatureInvalid,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
req := tt.setup()
err := signer.Verify(req)
if tt.wantErr == nil {
if err != nil {
t.Errorf("Verify() unexpected error = %v", err)
}
} else {
if err != tt.wantErr {
t.Errorf("Verify() error = %v, wantErr %v", err, tt.wantErr)
}
}
})
}
}
func TestSigner_DifferentKeys(t *testing.T) {
signer1 := NewSigner("secret-key-1")
signer2 := NewSigner("secret-key-2")
req := &ImageRequest{
SourceHost: "cdn.example.com",
SourcePath: "/photos/cat.jpg",
Size: Size{Width: 800, Height: 600},
Format: FormatWebP,
Expires: time.Now().Add(1 * time.Hour),
}
// Sign with key 1
req.Signature = signer1.Sign(req)
// Verify with key 1 should succeed
if err := signer1.Verify(req); err != nil {
t.Errorf("Verify() with same key failed: %v", err)
}
// Verify with key 2 should fail
if err := signer2.Verify(req); err != ErrSignatureInvalid {
t.Errorf("Verify() with different key should fail, got: %v", err)
}
}
func TestGenerateSignedURL(t *testing.T) {
signer := NewSigner("test-secret-key")
req := &ImageRequest{
SourceHost: "cdn.example.com",
SourcePath: "/photos/cat.jpg",
SourceQuery: "",
Size: Size{Width: 800, Height: 600},
Format: FormatWebP,
}
ttl := 1 * time.Hour
path, sig, exp := signer.GenerateSignedURL(req, ttl)
// Path should be correct format
expectedPath := "/v1/image/cdn.example.com/photos/cat.jpg/800x600.webp"
if path != expectedPath {
t.Errorf("GenerateSignedURL() path = %q, want %q", path, expectedPath)
}
// Signature should be non-empty
if sig == "" {
t.Error("GenerateSignedURL() produced empty signature")
}
// Expiration should be approximately now + TTL
expTime := time.Unix(exp, 0)
expectedExp := time.Now().Add(ttl)
if expTime.Sub(expectedExp) > time.Second {
t.Errorf("GenerateSignedURL() exp time off by too much")
}
// Request should have been updated with signature and expiration
if req.Signature != sig {
t.Errorf("GenerateSignedURL() didn't update request signature")
}
}
func TestGenerateSignedURL_OrigSize(t *testing.T) {
signer := NewSigner("test-secret-key")
req := &ImageRequest{
SourceHost: "cdn.example.com",
SourcePath: "/photos/cat.jpg",
Size: Size{Width: 0, Height: 0}, // Original size
Format: FormatPNG,
}
path, _, _ := signer.GenerateSignedURL(req, time.Hour)
expectedPath := "/v1/image/cdn.example.com/photos/cat.jpg/orig.png"
if path != expectedPath {
t.Errorf("GenerateSignedURL() path = %q, want %q", path, expectedPath)
}
}
func TestParseSignatureParams(t *testing.T) {
tests := []struct {
name string
sig string
expStr string
wantSig string
wantErr bool
checkTime bool
}{
{
name: "valid params",
sig: "abc123",
expStr: "1704067200",
wantSig: "abc123",
wantErr: false,
},
{
name: "empty expiration",
sig: "abc123",
expStr: "",
wantSig: "abc123",
wantErr: false,
},
{
name: "invalid expiration",
sig: "abc123",
expStr: "not-a-number",
wantErr: true,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
sig, exp, err := ParseSignatureParams(tt.sig, tt.expStr)
if tt.wantErr {
if err == nil {
t.Error("ParseSignatureParams() expected error, got nil")
}
return
}
if err != nil {
t.Errorf("ParseSignatureParams() unexpected error = %v", err)
return
}
if sig != tt.wantSig {
t.Errorf("sig = %q, want %q", sig, tt.wantSig)
}
if tt.expStr != "" && exp.IsZero() {
t.Error("exp should not be zero when expStr is provided")
}
})
}
}