Feat: proxy allow context type

proxy/read_seeker.go

@@ -7,18 +7,20 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"slices"
 	"strconv"
 )
 
 type HttpReadSeeker struct {
-	offset        int64
-	url           string
-	contentLength int64
-	method        string
-	body          io.Reader
-	client        *http.Client
-	headers       map[string]string
-	ctx           context.Context
+	offset              int64
+	url                 string
+	contentLength       int64
+	method              string
+	body                io.Reader
+	client              *http.Client
+	headers             map[string]string
+	ctx                 context.Context
+	allowedContentTypes []string
 }
 
 type HttpReadSeekerConf func(h *HttpReadSeeker)
@@ -82,6 +84,12 @@ func WithStartOffset(offset int64) HttpReadSeekerConf {
 	}
 }
 
+func AllowedContentTypes(types ...string) HttpReadSeekerConf {
+	return func(h *HttpReadSeeker) {
+		h.allowedContentTypes = types
+	}
+}
+
 func NewHttpReadSeeker(url string, conf ...HttpReadSeekerConf) *HttpReadSeeker {
 	rs := &HttpReadSeeker{
 		offset:        0,
@@ -130,11 +138,25 @@ func (h *HttpReadSeeker) Read(p []byte) (n int, err error) {
 		return 0, err
 	}
 	defer resp.Body.Close()
+	if err := h.checkContentType(resp.Header.Get("Content-Type")); err != nil {
+		return 0, err
+	}
+
 	n, err = io.ReadFull(resp.Body, p)
 	h.offset += int64(n)
 	return n, err
 }
 
+func (h *HttpReadSeeker) checkContentType(ct string) error {
+	if ct == "" {
+		return errors.New("content type is empty")
+	}
+	if len(h.allowedContentTypes) != 0 && slices.Index(h.allowedContentTypes, ct) == -1 {
+		return fmt.Errorf("content type `%s` not allowed", ct)
+	}
+	return nil
+}
+
 func (h *HttpReadSeeker) Seek(offset int64, whence int) (int64, error) {
 	switch whence {
 	case io.SeekStart:
@@ -155,6 +177,9 @@ func (h *HttpReadSeeker) Seek(offset int64, whence int) (int64, error) {
 				return 0, err
 			}
 			defer resp.Body.Close()
+			if err := h.checkContentType(resp.Header.Get("Content-Type")); err != nil {
+				return 0, err
+			}
 
 			h.contentLength, err = strconv.ParseInt(resp.Header.Get("Content-Length"), 10, 64)
 			if err != nil {