docs: update README and config to reflect exact-match-only whitelist

Remove suffix match documentation and config comments since whitelist
now only supports exact host matches.

Dockerfile

@@ -1,32 +1,31 @@
-# Lint stage — fast feedback on formatting and lint issues
-# golangci/golangci-lint:v2.10.1, 2026-03-01
-FROM golangci/golangci-lint@sha256:ea84d14c2fef724411be7dc45e09e6ef721d748315252b02df19a7e3113ee763 AS lint
+# Lint stage
+# golangci/golangci-lint:v2.10.1-alpine, 2026-02-17
+FROM golangci/golangci-lint:v2.10.1-alpine@sha256:33bc6b6156d4c7da87175f187090019769903d04dd408833b83083ed214b0ddf AS lint
 
-# Install CGO dependencies needed for static analysis of vips/libheif code
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    libvips-dev \
-    libheif-dev \
-    pkg-config \
-    && rm -rf /var/lib/apt/lists/*
+RUN apk add --no-cache make build-base vips-dev libheif-dev pkgconfig
 
 WORKDIR /src
+
+# Copy go mod files first for better layer caching
 COPY go.mod go.sum ./
 RUN go mod download
 
+# Copy source code
 COPY . .
 
+# Run formatting check and linter
 RUN make fmt-check
 RUN make lint
 
-# Build stage — tests and compilation
+# Build stage
 # golang:1.25.4-alpine, 2026-02-25
 FROM golang:1.25.4-alpine@sha256:d3f0cf7723f3429e3f9ed846243970b20a2de7bae6a5b66fc5914e228d831bbb AS builder
 
-ARG VERSION=dev
-
-# Force BuildKit to run the lint stage by creating a stage dependency
+# Depend on lint stage passing
 COPY --from=lint /src/go.sum /dev/null
 
+ARG VERSION=dev
+
 # Install build dependencies for CGO image libraries
 RUN apk add --no-cache \
     build-base \

README.md

@@ -98,9 +98,7 @@ expiration 1704067200:
 
 **Whitelist patterns:**
 
-- **Exact match**: `cdn.example.com` — matches only that host
-- **Suffix match**: `.example.com` — matches `cdn.example.com`,
-  `images.example.com`, and `example.com`
+- **Exact match only**: `cdn.example.com` — matches only that host
 
 ### Configuration
 

TODO.md

@@ -6,7 +6,7 @@ Remaining tasks sorted by priority for a working 1.0 release.
 
 ### Image Processing
 - [x] Add WebP encoding support (currently returns error)
-- [ ] Add AVIF encoding support (currently returns error)
+- [x] Add AVIF encoding support (implemented via govips)
 
 ### Manual Testing (verify auth/encrypted URLs work)
 - [ ] Manual test: visit `/`, see login form

config.example.yml

@@ -13,8 +13,7 @@ state_dir: ./data
 # Generate with: openssl rand -base64 32
 signing_key: "CHANGE_ME_generate_with_openssl_rand_base64_32"
 
-# Hosts that don't require signatures
-# Use "." prefix for wildcard subdomain matching (e.g., ".example.com" matches "cdn.example.com")
+# Hosts that don't require signatures (exact match only)
 whitelist_hosts:
   - s3.sneak.cloud
   - static.sneak.cloud

internal/imgcache/whitelist.go

@@ -6,22 +6,19 @@ import (
 )
 
 // HostWhitelist implements the Whitelist interface for checking allowed source hosts.
+// Only exact host matches are supported. Leading dots in patterns are stripped
+// (e.g. ".example.com" becomes an exact match for "example.com").
 type HostWhitelist struct {
-	// exactHosts contains hosts that must match exactly (e.g., "cdn.example.com")
-	exactHosts map[string]struct{}
-	// suffixHosts contains domain suffixes to match (e.g., ".example.com" matches "cdn.example.com")
-	suffixHosts []string
+	// hosts contains hosts that must match exactly (e.g., "cdn.example.com")
+	hosts map[string]struct{}
 }
 
 // NewHostWhitelist creates a whitelist from a list of host patterns.
-// Patterns starting with "." are treated as suffix matches.
-// Examples:
-//   - "cdn.example.com" - exact match only
-//   - ".example.com" - matches cdn.example.com, images.example.com, etc.
+// All patterns are treated as exact matches. Leading dots are stripped
+// for backwards compatibility (e.g. ".example.com" matches "example.com" only).
 func NewHostWhitelist(patterns []string) *HostWhitelist {
 	w := &HostWhitelist{
-		exactHosts:  make(map[string]struct{}),
-		suffixHosts: make([]string, 0),
+		hosts: make(map[string]struct{}),
 	}
 
 	for _, pattern := range patterns {
@@ -30,17 +27,22 @@ func NewHostWhitelist(patterns []string) *HostWhitelist {
 			continue
 		}
 
-		if strings.HasPrefix(pattern, ".") {
-			w.suffixHosts = append(w.suffixHosts, pattern)
-		} else {
-			w.exactHosts[pattern] = struct{}{}
+		// Strip leading dot — suffix matching is not supported.
+		// ".example.com" is treated as exact match for "example.com".
+		pattern = strings.TrimPrefix(pattern, ".")
+
+		if pattern == "" {
+			continue
 		}
+
+		w.hosts[pattern] = struct{}{}
 	}
 
 	return w
 }
 
 // IsWhitelisted checks if a URL's host is in the whitelist.
+// Only exact host matches are supported.
 func (w *HostWhitelist) IsWhitelisted(u *url.URL) bool {
 	if u == nil {
 		return false
@@ -51,32 +53,17 @@ func (w *HostWhitelist) IsWhitelisted(u *url.URL) bool {
 		return false
 	}
 
-	// Check exact match
-	if _, ok := w.exactHosts[host]; ok {
-		return true
-	}
+	_, ok := w.hosts[host]
 
-	// Check suffix match
-	for _, suffix := range w.suffixHosts {
-		if strings.HasSuffix(host, suffix) {
-			return true
-		}
-		// Also match if host equals the suffix without the leading dot
-		// e.g., pattern ".example.com" should match "example.com"
-		if host == strings.TrimPrefix(suffix, ".") {
-			return true
-		}
-	}
-
-	return false
+	return ok
 }
 
 // IsEmpty returns true if the whitelist has no entries.
 func (w *HostWhitelist) IsEmpty() bool {
-	return len(w.exactHosts) == 0 && len(w.suffixHosts) == 0
+	return len(w.hosts) == 0
 }
 
 // Count returns the total number of whitelist entries.
 func (w *HostWhitelist) Count() int {
-	return len(w.exactHosts) + len(w.suffixHosts)
+	return len(w.hosts)
 }

internal/imgcache/whitelist_test.go

@@ -31,41 +31,47 @@ func TestHostWhitelist_IsWhitelisted(t *testing.T) {
 			want:     false,
 		},
 		{
-			name:     "suffix match",
+			name:     "dot prefix does not enable suffix matching",
 			patterns: []string{".example.com"},
 			testURL:  "https://cdn.example.com/image.jpg",
-			want:     true,
+			want:     false,
 		},
 		{
-			name:     "suffix match deep subdomain",
+			name:     "dot prefix does not match deep subdomain",
 			patterns: []string{".example.com"},
 			testURL:  "https://cdn.images.example.com/image.jpg",
-			want:     true,
+			want:     false,
 		},
 		{
-			name:     "suffix match apex domain",
+			name:     "dot prefix stripped matches apex domain exactly",
 			patterns: []string{".example.com"},
 			testURL:  "https://example.com/image.jpg",
 			want:     true,
 		},
 		{
-			name:     "suffix match not found",
+			name:     "dot prefix does not match unrelated domain",
 			patterns: []string{".example.com"},
 			testURL:  "https://notexample.com/image.jpg",
 			want:     false,
 		},
 		{
-			name:     "suffix match partial not allowed",
+			name:     "dot prefix does not match partial domain",
 			patterns: []string{".example.com"},
 			testURL:  "https://fakeexample.com/image.jpg",
 			want:     false,
 		},
 		{
-			name:     "multiple patterns",
-			patterns: []string{"cdn.example.com", ".images.org", "static.test.net"},
+			name:     "multiple patterns exact only",
+			patterns: []string{"cdn.example.com", "photos.images.org", "static.test.net"},
 			testURL:  "https://photos.images.org/image.jpg",
 			want:     true,
 		},
+		{
+			name:     "multiple patterns no suffix match",
+			patterns: []string{"cdn.example.com", ".images.org", "static.test.net"},
+			testURL:  "https://photos.images.org/image.jpg",
+			want:     false,
+		},
 		{
 			name:     "empty whitelist",
 			patterns: []string{},
@@ -90,6 +96,12 @@ func TestHostWhitelist_IsWhitelisted(t *testing.T) {
 			testURL:  "https://cdn.example.com/image.jpg",
 			want:     true,
 		},
+		{
+			name:     "whitespace dot prefix stripped matches exactly",
+			patterns: []string{"  .other.com  "},
+			testURL:  "https://other.com/image.jpg",
+			want:     true,
+		},
 	}
 
 	for _, tt := range tests {
@@ -139,6 +151,11 @@ func TestHostWhitelist_IsEmpty(t *testing.T) {
 			patterns: []string{"example.com"},
 			want:     false,
 		},
+		{
+			name:     "dot prefix entry still counts",
+			patterns: []string{".example.com"},
+			want:     false,
+		},
 	}
 
 	for _, tt := range tests {
@@ -168,7 +185,7 @@ func TestHostWhitelist_Count(t *testing.T) {
 			want:     3,
 		},
 		{
-			name:     "suffix hosts only",
+			name:     "dot prefix hosts treated as exact",
 			patterns: []string{".a.com", ".b.com"},
 			want:     2,
 		},
@@ -177,6 +194,11 @@ func TestHostWhitelist_Count(t *testing.T) {
 			patterns: []string{"exact.com", ".suffix.com"},
 			want:     2,
 		},
+		{
+			name:     "dot prefix deduplicates with exact",
+			patterns: []string{"example.com", ".example.com"},
+			want:     1,
+		},
 	}
 
 	for _, tt := range tests {

scripts/manual-test.sh

@@ -48,7 +48,7 @@ fi
 
 # Test 3: Wrong password shows error
 echo "--- Test 3: Login with wrong password ---"
-WRONG_LOGIN=$(curl -sf -X POST "$BASE_URL/" -d "password=wrong-key" -c "$COOKIE_JAR")
+WRONG_LOGIN=$(curl -sf -X POST "$BASE_URL/" -d "key=wrong-key" -c "$COOKIE_JAR")
 if echo "$WRONG_LOGIN" | grep -qi "invalid\|error\|incorrect\|wrong"; then
     pass "Wrong password shows error message"
 else
@@ -57,7 +57,7 @@ fi
 
 # Test 4: Correct password redirects to generator
 echo "--- Test 4: Login with correct signing key ---"
-curl -sf -X POST "$BASE_URL/" -d "password=$SIGNING_KEY" -c "$COOKIE_JAR" -b "$COOKIE_JAR" -L -o /dev/null
+curl -sf -X POST "$BASE_URL/" -d "key=$SIGNING_KEY" -c "$COOKIE_JAR" -b "$COOKIE_JAR" -L -o /dev/null
 GENERATOR_PAGE=$(curl -sf "$BASE_URL/" -b "$COOKIE_JAR")
 if echo "$GENERATOR_PAGE" | grep -qi "generate\|url\|source\|logout"; then
     pass "Correct password shows generator page"
@@ -68,12 +68,12 @@ fi
 # Test 5: Generate encrypted URL
 echo "--- Test 5: Generate encrypted URL ---"
 GEN_RESULT=$(curl -sf -X POST "$BASE_URL/generate" -b "$COOKIE_JAR" \
-    -d "source_url=$TEST_IMAGE_URL" \
+    -d "url=$TEST_IMAGE_URL" \
     -d "width=800" \
     -d "height=600" \
     -d "format=jpeg" \
     -d "quality=85" \
-    -d "fit_mode=cover" \
+    -d "fit=cover" \
     -d "ttl=3600")
 if echo "$GEN_RESULT" | grep -q "/v1/e/"; then
     pass "Encrypted URL generated"
@@ -121,10 +121,10 @@ fi
 # Test 9: Generate short-TTL URL and verify expiration
 echo "--- Test 9: Expired URL returns 410 ---"
 # Login again
-curl -sf -X POST "$BASE_URL/" -d "password=$SIGNING_KEY" -c "$COOKIE_JAR" -b "$COOKIE_JAR" -L -o /dev/null
+curl -sf -X POST "$BASE_URL/" -d "key=$SIGNING_KEY" -c "$COOKIE_JAR" -b "$COOKIE_JAR" -L -o /dev/null
 # Generate URL with 1 second TTL
 GEN_RESULT=$(curl -sf -X POST "$BASE_URL/generate" -b "$COOKIE_JAR" \
-    -d "source_url=$TEST_IMAGE_URL" \
+    -d "url=$TEST_IMAGE_URL" \
     -d "width=100" \
     -d "height=100" \
     -d "format=jpeg" \