go-gemini/request.go
2021-02-14 15:50:41 -05:00

134 lines
3.7 KiB
Go

package gemini
import (
"bufio"
"context"
"crypto/tls"
"io"
"net"
"net/url"
)
// A Request represents a Gemini request received by a server or to be sent
// by a client.
//
// The field semantics differ slightly between client and server usage.
// In addition to the notes on the fields below, see the documentation
// for Request.Write and TODO: RoundTripper.
type Request struct {
// URL specifies the URL being requested (for server
// requests) or the URL to access (for client requests).
URL *url.URL
// For client requests, Host specifies the server to connect to.
// Host must contain a port.
// This field is ignored by the Gemini server.
Host string
// Certificate specifies the TLS certificate to use for the request.
//
// On the server side, if the client provided a certificate then
// Certificate.Leaf is guaranteed to be non-nil.
Certificate *tls.Certificate
// RemoteAddr allows Gemini servers and other software to record
// the network address that sent the request, usually for
// logging. This field is not filled in by ReadRequest and
// has no defined format. The Gemini server in this package
// sets RemoteAddr to an "IP:port" address before invoking a
// handler.
// This field is ignored by the Gemini client.
RemoteAddr net.Addr
// TLS allows Gemini servers and other software to record
// information about the TLS connection on which the request
// was received. This field is not filled in by ReadRequest.
// The Gemini server in this package sets the field for
// TLS-enabled connections before invoking a handler;
// otherwise it leaves the field nil.
// This field is ignored by the Gemini client.
TLS *tls.ConnectionState
// Context specifies the context to use for client requests.
// If Context is nil, the background context will be used.
// This field is ignored by the Gemini server.
Context context.Context
}
// NewRequest returns a new request. The host is inferred from the URL.
func NewRequest(rawurl string) (*Request, error) {
u, err := url.Parse(rawurl)
if err != nil {
return nil, err
}
return NewRequestFromURL(u), nil
}
// NewRequestFromURL returns a new request for the given URL.
// The host is inferred from the URL.
//
// Callers should be careful that the URL query is properly escaped.
// See the documentation for QueryEscape for more information.
func NewRequestFromURL(url *url.URL) *Request {
host := url.Host
if url.Port() == "" {
host += ":1965"
}
return &Request{
URL: url,
Host: host,
}
}
// ReadRequest reads and parses an incoming request from r.
//
// ReadRequest is a low-level function and should only be used
// for specialized applications; most code should use the Server
// to read requests and handle them via the Handler interface.
func ReadRequest(r io.Reader) (*Request, error) {
// Read URL
br := bufio.NewReaderSize(r, 1026)
rawurl, err := br.ReadString('\r')
if err != nil {
return nil, err
}
// Read terminating line feed
if b, err := br.ReadByte(); err != nil {
return nil, err
} else if b != '\n' {
return nil, ErrInvalidRequest
}
// Trim carriage return
rawurl = rawurl[:len(rawurl)-1]
// Validate URL
if len(rawurl) > 1024 {
return nil, ErrInvalidRequest
}
u, err := url.Parse(rawurl)
if err != nil {
return nil, err
}
if u.User != nil {
// User is not allowed
return nil, ErrInvalidURL
}
return &Request{URL: u}, nil
}
// Write writes a Gemini request in wire format.
// This method consults the request URL only.
func (r *Request) Write(w *bufio.Writer) error {
url := r.URL.String()
// User is invalid
if r.URL.User != nil || len(url) > 1024 {
return ErrInvalidURL
}
if _, err := w.WriteString(url); err != nil {
return err
}
if _, err := w.Write(crlf); err != nil {
return err
}
return nil
}