goget/internal/protocol/http/handler.go

//go:build linux || freebsd
// +build linux freebsd

package http

import (
	"fmt"
	"mime"
	"net/http"
	"net/url"
	"path/filepath"
	"strings"
)

// URLInfo contains extracted information from an HTTP URL
type URLInfo struct {
	Scheme   string
	Host     string
	Port     string
	Path     string
	Query    string
	Fragment string
	User     *url.Userinfo
}

// Handler contains HTTP-specific logic
type Handler struct {
	client *Client
}

// NewHandler creates new handler
func NewHandler(client *Client) *Handler {
	return &Handler{client: client}
}

// ParseHTTPURL parses an HTTP URL and extracts information
func ParseHTTPURL(u *url.URL) (*URLInfo, error) {
	if u.Scheme != "http" && u.Scheme != "https" {
		return nil, fmt.Errorf("invalid http url scheme: %s", u.Scheme)
	}

	host := u.Hostname()
	port := u.Port()
	if port == "" {
		if u.Scheme == "https" {
			port = "443"
		} else {
			port = "80"
		}
	}

	return &URLInfo{
		Scheme:   u.Scheme,
		Host:     host,
		Port:     port,
		Path:     u.Path,
		Query:    u.RawQuery,
		Fragment: u.Fragment,
		User:     u.User,
	}, nil
}

// GetContentType extracts Content-Type from the response
func GetContentType(resp *http.Response) string {
	return resp.Header.Get("Content-Type")
}

// GetContentLength extracts Content-Length from the response
func GetContentLength(resp *http.Response) int64 {
	return resp.ContentLength
}

// GetContentEncoding extracts Content-Encoding from the response
func GetContentEncoding(resp *http.Response) string {
	return resp.Header.Get("Content-Encoding")
}

// GetETag extracts ETag from the response
func GetETag(resp *http.Response) string {
	return resp.Header.Get("ETag")
}

// GetLastModified extracts Last-Modified from the response
func GetLastModified(resp *http.Response) string {
	return resp.Header.Get("Last-Modified")
}

// SupportsRangeCheck checks whether the server supports range requests
func SupportsRangeCheck(resp *http.Response) bool {
	acceptRanges := resp.Header.Get("Accept-Ranges")
	return strings.ToLower(acceptRanges) == "bytes"
}

// IsRedirect checks whether the response is a redirect
func IsRedirect(statusCode int) bool {
	return statusCode >= 300 && statusCode < 400
}

// GetRedirectLocation gets the Location header from a redirect response
func GetRedirectLocation(resp *http.Response) string {
	return resp.Header.Get("Location")
}

// BuildURLWithQuery creates a URL with query parameters
func BuildURLWithQuery(base *url.URL, params map[string]string) (*url.URL, error) {
	if base == nil {
		return nil, fmt.Errorf("base url cannot be nil")
	}

	result := *base
	query := result.Query()

	for key, value := range params {
		query.Set(key, value)
	}

	result.RawQuery = query.Encode()
	return &result, nil
}

// GetUserinfo extracts authentication credentials from the URL
func GetUserinfo(u *url.URL) (username, password string, ok bool) {
	if u.User == nil {
		return "", "", false
	}
	username = u.User.Username()
	password, ok = u.User.Password()
	return username, password, true
}

// IsSecure checks whether the URL uses HTTPS
func IsSecure(u *url.URL) bool {
	return u.Scheme == "https"
}

// GetDefaultPortForScheme returns the default port for the scheme
func GetDefaultPortForScheme(scheme string) string {
	switch scheme {
	case "https":
		return "443"
	case "http":
		return "80"
	default:
		return ""
	}
}

// ParseContentDisposition extracts filename from Content-Disposition header
func ParseContentDisposition(headerValue string) string {
	if headerValue == "" {
		return ""
	}

	_, params, err := mime.ParseMediaType(headerValue)
	if err != nil {
		return ""
	}

	// Try filename* first (RFC 5987, extended filename)
	if filename, ok := params["filename*"]; ok {
		return filename
	}

	// Fall back to filename
	if filename, ok := params["filename"]; ok {
		return filename
	}

	return ""
}

// SanitizeFilename removes path components from a filename for security
func SanitizeFilename(name string) string {
	name = filepath.Base(name)
	if name == "" || name == "." || name == ".." {
		return ""
	}
	return name
}