1 files changed, 147 insertions, 0 deletions
diff --git a/internal/reader/fetcher/response_handler.go b/internal/reader/fetcher/response_handler.go
new file mode 100644
index 00000000..1283b405
--- /dev/null
+++ b/internal/reader/fetcher/response_handler.go
@@ -0,0 +1,147 @@
+// SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package fetcher // import "miniflux.app/v2/internal/reader/fetcher"
+
+import (
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+
+	"miniflux.app/v2/internal/locale"
+)
+
+type ResponseHandler struct {
+	httpResponse *http.Response
+	clientErr    error
+}
+
+func NewResponseHandler(httpResponse *http.Response, clientErr error) *ResponseHandler {
+	return &ResponseHandler{httpResponse: httpResponse, clientErr: clientErr}
+}
+
+func (r *ResponseHandler) EffectiveURL() string {
+	return r.httpResponse.Request.URL.String()
+}
+
+func (r *ResponseHandler) ContentType() string {
+	return r.httpResponse.Header.Get("Content-Type")
+}
+
+func (r *ResponseHandler) LastModified() string {
+	// Ignore caching headers for feeds that do not want any cache.
+	if r.httpResponse.Header.Get("Expires") == "0" {
+		return ""
+	}
+	return r.httpResponse.Header.Get("Last-Modified")
+}
+
+func (r *ResponseHandler) ETag() string {
+	// Ignore caching headers for feeds that do not want any cache.
+	if r.httpResponse.Header.Get("Expires") == "0" {
+		return ""
+	}
+	return r.httpResponse.Header.Get("ETag")
+}
+
+func (r *ResponseHandler) IsModified(lastEtagValue, lastModifiedValue string) bool {
+	if r.httpResponse.StatusCode == http.StatusNotModified {
+		return false
+	}
+
+	if r.ETag() != "" && r.ETag() == lastEtagValue {
+		return false
+	}
+
+	if r.LastModified() != "" && r.LastModified() == lastModifiedValue {
+		return false
+	}
+
+	return true
+}
+
+func (r *ResponseHandler) Close() {
+	if r.httpResponse != nil && r.httpResponse.Body != nil && r.clientErr == nil {
+		r.httpResponse.Body.Close()
+	}
+}
+
+func (r *ResponseHandler) Body(maxBodySize int64) io.ReadCloser {
+	return http.MaxBytesReader(nil, r.httpResponse.Body, maxBodySize)
+}
+
+func (r *ResponseHandler) ReadBody(maxBodySize int64) ([]byte, *locale.LocalizedErrorWrapper) {
+	limitedReader := http.MaxBytesReader(nil, r.httpResponse.Body, maxBodySize)
+
+	buffer, err := io.ReadAll(limitedReader)
+	if err != nil && err != io.EOF {
+		if err == io.ErrUnexpectedEOF {
+			return nil, locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: response body too large: %w", err), "error.http_response_too_large")
+		}
+
+		return nil, locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: unable to read response body: %w", err), "error.http_body_read", err)
+	}
+
+	if len(buffer) == 0 {
+		return nil, locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: empty response body"), "error.http_empty_response_body")
+	}
+
+	return buffer, nil
+}
+
+func (r *ResponseHandler) LocalizedError() *locale.LocalizedErrorWrapper {
+	if r.clientErr != nil {
+		switch r.clientErr.(type) {
+		case x509.CertificateInvalidError, x509.UnknownAuthorityError, x509.HostnameError:
+			return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: %w", r.clientErr), "error.tls_error", r.clientErr.Error())
+		case *net.OpError:
+			return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: %w", r.clientErr), "error.network_operation", r.clientErr.Error())
+		case net.Error:
+			networkErr := r.clientErr.(net.Error)
+			if networkErr.Timeout() {
+				return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: %w", r.clientErr), "error.network_timeout", r.clientErr.Error())
+			}
+		}
+
+		if errors.Is(r.clientErr, io.EOF) {
+			return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: %w", r.clientErr), "error.http_empty_response")
+		}
+
+		return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: %w", r.clientErr), "error.http_client_error", r.clientErr.Error())
+	}
+
+	switch r.httpResponse.StatusCode {
+	case http.StatusUnauthorized:
+		return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: access unauthorized (401 status code)"), "error.http_not_authorized")
+	case http.StatusForbidden:
+		return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: access forbidden (403 status code)"), "error.http_forbidden")
+	case http.StatusTooManyRequests:
+		return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: too many requests (429 status code)"), "error.http_too_many_requests")
+	case http.StatusNotFound, http.StatusGone:
+		return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: resource not found (%d status code)", r.httpResponse.StatusCode), "error.http_resource_not_found")
+	case http.StatusInternalServerError:
+		return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: remote server error (%d status code)", r.httpResponse.StatusCode), "error.http_internal_server_error")
+	case http.StatusBadGateway:
+		return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: bad gateway (%d status code)", r.httpResponse.StatusCode), "error.http_bad_gateway")
+	case http.StatusServiceUnavailable:
+		return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: service unavailable (%d status code)", r.httpResponse.StatusCode), "error.http_service_unavailable")
+	case http.StatusGatewayTimeout:
+		return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: gateway timeout (%d status code)", r.httpResponse.StatusCode), "error.http_gateway_timeout")
+	}
+
+	if r.httpResponse.StatusCode >= 400 {
+		return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: unexpected status code (%d status code)", r.httpResponse.StatusCode), "error.http_unexpected_status_code", r.httpResponse.StatusCode)
+	}
+
+	if r.httpResponse.StatusCode != 304 {
+		// Content-Length = -1 when no Content-Length header is sent.
+		if r.httpResponse.ContentLength == 0 {
+			return locale.NewLocalizedErrorWrapper(fmt.Errorf("fetcher: empty response body"), "error.http_empty_response_body")
+		}
+	}
+
+	return nil
+}