refactor: switch cache to use http.Header

internal/cache/api.go

@@ -6,7 +6,7 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"io"
-	"net/textproto"
+	"net/http"
 	"time"
 
 	"github.com/alecthomas/errors"
@@ -97,8 +97,8 @@ func (k *Key) MarshalText() ([]byte, error) {
 
 // FilterTransportHeaders returns a copy of the given headers with standard HTTP transport headers removed.
 // These headers are typically added by HTTP clients/servers and should not be cached.
-func FilterTransportHeaders(headers textproto.MIMEHeader) textproto.MIMEHeader {
-	filtered := make(textproto.MIMEHeader)
+func FilterTransportHeaders(headers http.Header) http.Header {
+	filtered := make(http.Header)
 	for key, values := range headers {
 		// Skip standard HTTP headers added by transport layer or that shouldn't be cached
 		if key == "Content-Length" || key == "Date" || key == "Accept-Encoding" ||
@@ -120,21 +120,21 @@ type Cache interface {
 	//
 	// Expired files MUST not be returned.
 	// Must return os.ErrNotExist if the file does not exist.
-	Stat(ctx context.Context, key Key) (textproto.MIMEHeader, error)
+	Stat(ctx context.Context, key Key) (http.Header, error)
 	// Open an existing file in the cache.
 	//
 	// Expired files MUST NOT be returned.
 	// The returned headers MUST include a Last-Modified header.
 	// Must return os.ErrNotExist if the file does not exist.
-	Open(ctx context.Context, key Key) (io.ReadCloser, textproto.MIMEHeader, error)
+	Open(ctx context.Context, key Key) (io.ReadCloser, http.Header, error)
 	// Create a new file in the cache.
 	//
 	// If "ttl" is zero, a maximum TTL MUST be used by the implementation.
 	//
 	// The file MUST NOT be available for read until completely written and closed.
 	//
 	// If the context is cancelled the object MUST NOT be made available in the cache.
-	Create(ctx context.Context, key Key, headers textproto.MIMEHeader, ttl time.Duration) (io.WriteCloser, error)
+	Create(ctx context.Context, key Key, headers http.Header, ttl time.Duration) (io.WriteCloser, error)
 	// Delete a file from the cache.
 	//
 	// MUST be atomic.

internal/cache/cachetest/suite.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"io"
 	"net/http"
-	"net/textproto"
 	"os"
 	"testing"
 	"time"
@@ -215,7 +214,7 @@ func testHeaders(t *testing.T, c cache.Cache) {
 	key := cache.NewKey("test-key-with-headers")
 
 	// Create headers to store
-	headers := textproto.MIMEHeader{
+	headers := http.Header{
 		"Content-Type":   []string{"application/json"},
 		"Cache-Control":  []string{"max-age=3600"},
 		"X-Custom-Field": []string{"custom-value"},
@@ -258,7 +257,7 @@ func testContextCancellation(t *testing.T, c cache.Cache) {
 
 	// Create an object with the cancellable context
 	key := cache.NewKey("test-cancelled")
-	writer, err := c.Create(cancelledCtx, key, textproto.MIMEHeader{}, time.Hour)
+	writer, err := c.Create(cancelledCtx, key, http.Header{}, time.Hour)
 	assert.NoError(t, err)
 
 	// Write some data
@@ -310,7 +309,7 @@ func testLastModified(t *testing.T, c cache.Cache) {
 	// Test with explicit Last-Modified header
 	key2 := cache.NewKey("test-last-modified-explicit")
 	explicitTime := time.Date(2023, 1, 15, 12, 30, 0, 0, time.UTC)
-	explicitHeaders := textproto.MIMEHeader{
+	explicitHeaders := http.Header{
 		"Last-Modified": []string{explicitTime.Format(http.TimeFormat)},
 	}
 

internal/cache/disk.go

@@ -7,7 +7,6 @@ import (
 	"log/slog"
 	"maps"
 	"net/http"
-	"net/textproto"
 	"os"
 	"path/filepath"
 	"sort"
@@ -130,14 +129,14 @@ func (d *Disk) Size() int64 {
 	return d.size.Load()
 }
 
-func (d *Disk) Create(ctx context.Context, key Key, headers textproto.MIMEHeader, ttl time.Duration) (io.WriteCloser, error) {
+func (d *Disk) Create(ctx context.Context, key Key, headers http.Header, ttl time.Duration) (io.WriteCloser, error) {
 	if ttl > d.config.MaxTTL || ttl == 0 {
 		ttl = d.config.MaxTTL
 	}
 
 	now := time.Now()
 	// Clone headers to avoid concurrent map writes
-	clonedHeaders := make(textproto.MIMEHeader)
+	clonedHeaders := make(http.Header)
 	maps.Copy(clonedHeaders, headers)
 	if clonedHeaders.Get("Last-Modified") == "" {
 		clonedHeaders.Set("Last-Modified", now.UTC().Format(http.TimeFormat))
@@ -204,7 +203,7 @@ func (d *Disk) Delete(_ context.Context, key Key) error {
 	return nil
 }
 
-func (d *Disk) Stat(ctx context.Context, key Key) (textproto.MIMEHeader, error) {
+func (d *Disk) Stat(ctx context.Context, key Key) (http.Header, error) {
 	path := d.keyToPath(key)
 	fullPath := filepath.Join(d.config.Root, path)
 
@@ -229,7 +228,7 @@ func (d *Disk) Stat(ctx context.Context, key Key) (textproto.MIMEHeader, error)
 	return headers, nil
 }
 
-func (d *Disk) Open(ctx context.Context, key Key) (io.ReadCloser, textproto.MIMEHeader, error) {
+func (d *Disk) Open(ctx context.Context, key Key) (io.ReadCloser, http.Header, error) {
 	path := d.keyToPath(key)
 	fullPath := filepath.Join(d.config.Root, path)
 
@@ -378,7 +377,7 @@ type diskWriter struct {
 	path      string
 	tempPath  string
 	expiresAt time.Time
-	headers   textproto.MIMEHeader
+	headers   http.Header
 	size      int64
 	ctx       context.Context
 }

internal/cache/disk_metadb.go

@@ -2,7 +2,7 @@ package cache
 
 import (
 	"encoding/json"
-	"net/textproto"
+	"net/http"
 	"time"
 
 	"github.com/alecthomas/errors"
@@ -55,7 +55,7 @@ func (s *diskMetaDB) setTTL(key Key, expiresAt time.Time) error {
 	}))
 }
 
-func (s *diskMetaDB) set(key Key, expiresAt time.Time, headers textproto.MIMEHeader) error {
+func (s *diskMetaDB) set(key Key, expiresAt time.Time, headers http.Header) error {
 	ttlBytes, err := expiresAt.MarshalBinary()
 	if err != nil {
 		return errors.Errorf("failed to marshal TTL: %w", err)
@@ -90,8 +90,8 @@ func (s *diskMetaDB) getTTL(key Key) (time.Time, error) {
 	return expiresAt, errors.WithStack(err)
 }
 
-func (s *diskMetaDB) getHeaders(key Key) (textproto.MIMEHeader, error) {
-	var headers textproto.MIMEHeader
+func (s *diskMetaDB) getHeaders(key Key) (http.Header, error) {
+	var headers http.Header
 	err := s.db.View(func(tx *bbolt.Tx) error {
 		bucket := tx.Bucket(headersBucketName)
 		headersBytes := bucket.Get(key[:])

internal/cache/http.go

@@ -4,7 +4,6 @@ import (
 	"io"
 	"maps"
 	"net/http"
-	"net/textproto"
 	"os"
 
 	"github.com/alecthomas/errors"
@@ -27,7 +26,7 @@ func Fetch(client *http.Client, r *http.Request, c Cache) (*http.Response, error
 			Proto:         "HTTP/1.1",
 			ProtoMajor:    1,
 			ProtoMinor:    1,
-			Header:        http.Header(headers),
+			Header:        headers,
 			Body:          cr,
 			ContentLength: -1,
 			Request:       r,
@@ -53,7 +52,7 @@ func FetchDirect(client *http.Client, r *http.Request, c Cache, key Key) (*http.
 		return resp, nil
 	}
 
-	responseHeaders := textproto.MIMEHeader(maps.Clone(resp.Header))
+	responseHeaders := maps.Clone(resp.Header)
 	cw, err := c.Create(r.Context(), key, responseHeaders, 0)
 	if err != nil {
 		_ = resp.Body.Close()

internal/cache/memory.go

@@ -7,7 +7,6 @@ import (
 	"io"
 	"maps"
 	"net/http"
-	"net/textproto"
 	"os"
 	"sync"
 	"time"
@@ -33,7 +32,7 @@ type MemoryConfig struct {
 type memoryEntry struct {
 	data      []byte
 	expiresAt time.Time
-	headers   textproto.MIMEHeader
+	headers   http.Header
 }
 
 type Memory struct {
@@ -53,7 +52,7 @@ func NewMemory(ctx context.Context, config MemoryConfig) (*Memory, error) {
 
 func (m *Memory) String() string { return fmt.Sprintf("memory:%dMB", m.config.LimitMB) }
 
-func (m *Memory) Stat(_ context.Context, key Key) (textproto.MIMEHeader, error) {
+func (m *Memory) Stat(_ context.Context, key Key) (http.Header, error) {
 	m.mu.RLock()
 	defer m.mu.RUnlock()
 
@@ -69,7 +68,7 @@ func (m *Memory) Stat(_ context.Context, key Key) (textproto.MIMEHeader, error)
 	return entry.headers, nil
 }
 
-func (m *Memory) Open(_ context.Context, key Key) (io.ReadCloser, textproto.MIMEHeader, error) {
+func (m *Memory) Open(_ context.Context, key Key) (io.ReadCloser, http.Header, error) {
 	m.mu.RLock()
 	defer m.mu.RUnlock()
 
@@ -85,14 +84,14 @@ func (m *Memory) Open(_ context.Context, key Key) (io.ReadCloser, textproto.MIME
 	return io.NopCloser(bytes.NewReader(entry.data)), entry.headers, nil
 }
 
-func (m *Memory) Create(ctx context.Context, key Key, headers textproto.MIMEHeader, ttl time.Duration) (io.WriteCloser, error) {
+func (m *Memory) Create(ctx context.Context, key Key, headers http.Header, ttl time.Duration) (io.WriteCloser, error) {
 	if ttl == 0 {
 		ttl = m.config.MaxTTL
 	}
 
 	now := time.Now()
 	// Clone headers to avoid concurrent map writes
-	clonedHeaders := make(textproto.MIMEHeader)
+	clonedHeaders := make(http.Header)
 	maps.Copy(clonedHeaders, headers)
 	if clonedHeaders.Get("Last-Modified") == "" {
 		clonedHeaders.Set("Last-Modified", now.UTC().Format(http.TimeFormat))
@@ -136,7 +135,7 @@ type memoryWriter struct {
 	key       Key
 	buf       *bytes.Buffer
 	expiresAt time.Time
-	headers   textproto.MIMEHeader
+	headers   http.Header
 	closed    bool
 	ctx       context.Context
 }

internal/cache/remote.go

@@ -6,7 +6,6 @@ import (
 	"io"
 	"maps"
 	"net/http"
-	"net/textproto"
 	"os"
 	"time"
 
@@ -32,7 +31,7 @@ func NewRemote(baseURL string) *Remote {
 func (c *Remote) String() string { return "remote:" + c.baseURL }
 
 // Open retrieves an object from the remote.
-func (c *Remote) Open(ctx context.Context, key Key) (io.ReadCloser, textproto.MIMEHeader, error) {
+func (c *Remote) Open(ctx context.Context, key Key) (io.ReadCloser, http.Header, error) {
 	url := fmt.Sprintf("%s/%s", c.baseURL, key.String())
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	if err != nil {
@@ -53,13 +52,13 @@ func (c *Remote) Open(ctx context.Context, key Key) (io.ReadCloser, textproto.MI
 	}
 
 	// Filter out HTTP transport headers
-	headers := FilterTransportHeaders(textproto.MIMEHeader(resp.Header))
+	headers := FilterTransportHeaders(resp.Header)
 
 	return resp.Body, headers, nil
 }
 
 // Stat retrieves headers for an object from the remote.
-func (c *Remote) Stat(ctx context.Context, key Key) (textproto.MIMEHeader, error) {
+func (c *Remote) Stat(ctx context.Context, key Key) (http.Header, error) {
 	url := fmt.Sprintf("%s/%s", c.baseURL, key.String())
 	req, err := http.NewRequestWithContext(ctx, http.MethodHead, url, nil)
 	if err != nil {
@@ -81,13 +80,13 @@ func (c *Remote) Stat(ctx context.Context, key Key) (textproto.MIMEHeader, error
 	}
 
 	// Filter out HTTP transport headers
-	headers := FilterTransportHeaders(textproto.MIMEHeader(resp.Header))
+	headers := FilterTransportHeaders(resp.Header)
 
 	return headers, nil
 }
 
 // Create stores a new object in the remote.
-func (c *Remote) Create(ctx context.Context, key Key, headers textproto.MIMEHeader, ttl time.Duration) (io.WriteCloser, error) {
+func (c *Remote) Create(ctx context.Context, key Key, headers http.Header, ttl time.Duration) (io.WriteCloser, error) {
 	pr, pw := io.Pipe()
 
 	url := fmt.Sprintf("%s/%s", c.baseURL, key.String())

internal/cache/s3.go

@@ -9,7 +9,6 @@ import (
 	"log/slog"
 	"maps"
 	"net/http"
-	"net/textproto"
 	"os"
 	"runtime"
 	"time"
@@ -162,7 +161,7 @@ func (s *S3) keyToPath(key Key) string {
 	return hexKey[:2] + "/" + hexKey
 }
 
-func (s *S3) Stat(ctx context.Context, key Key) (textproto.MIMEHeader, error) {
+func (s *S3) Stat(ctx context.Context, key Key) (http.Header, error) {
 	objectName := s.keyToPath(key)
 
 	// Get object info to check metadata
@@ -190,7 +189,7 @@ func (s *S3) Stat(ctx context.Context, key Key) (textproto.MIMEHeader, error) {
 
 	// Retrieve headers from metadata
 	// Note: UserMetadata keys are returned WITHOUT the "X-Amz-Meta-" prefix by minio-go
-	headers := make(textproto.MIMEHeader)
+	headers := make(http.Header)
 	if headersJSON := objInfo.UserMetadata["Headers"]; headersJSON != "" {
 		if err := json.Unmarshal([]byte(headersJSON), &headers); err != nil {
 			return nil, errors.Errorf("failed to unmarshal headers: %w", err)
@@ -205,7 +204,7 @@ func (s *S3) Stat(ctx context.Context, key Key) (textproto.MIMEHeader, error) {
 	return headers, nil
 }
 
-func (s *S3) Open(ctx context.Context, key Key) (io.ReadCloser, textproto.MIMEHeader, error) {
+func (s *S3) Open(ctx context.Context, key Key) (io.ReadCloser, http.Header, error) {
 	objectName := s.keyToPath(key)
 
 	// Get object info to retrieve metadata and check expiration
@@ -230,7 +229,7 @@ func (s *S3) Open(ctx context.Context, key Key) (io.ReadCloser, textproto.MIMEHe
 	}
 
 	// Retrieve headers from metadata
-	headers := make(textproto.MIMEHeader)
+	headers := make(http.Header)
 	if headersJSON := objInfo.UserMetadata["Headers"]; headersJSON != "" {
 		if err := json.Unmarshal([]byte(headersJSON), &headers); err != nil {
 			return nil, nil, errors.Errorf("failed to unmarshal headers: %w", err)
@@ -251,13 +250,13 @@ func (s *S3) Open(ctx context.Context, key Key) (io.ReadCloser, textproto.MIMEHe
 	return obj, headers, nil
 }
 
-func (s *S3) Create(ctx context.Context, key Key, headers textproto.MIMEHeader, ttl time.Duration) (io.WriteCloser, error) {
+func (s *S3) Create(ctx context.Context, key Key, headers http.Header, ttl time.Duration) (io.WriteCloser, error) {
 	if ttl > s.config.MaxTTL || ttl == 0 {
 		ttl = s.config.MaxTTL
 	}
 
 	// Clone headers to avoid concurrent access issues
-	clonedHeaders := make(textproto.MIMEHeader)
+	clonedHeaders := make(http.Header)
 	maps.Copy(clonedHeaders, headers)
 
 	expiresAt := time.Now().Add(ttl)
@@ -296,7 +295,7 @@ type s3Writer struct {
 	key       Key
 	pipe      *io.PipeWriter
 	expiresAt time.Time
-	headers   textproto.MIMEHeader
+	headers   http.Header
 	ctx       context.Context
 	errCh     chan error
 }