diff options
| -rw-r--r-- | src/lib/http/server.go | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/src/lib/http/server.go b/src/lib/http/server.go index 375818235..c1de5de78 100644 --- a/src/lib/http/server.go +++ b/src/lib/http/server.go @@ -21,6 +21,7 @@ import ( "os"; "path"; "strconv"; + "strings"; ) // Errors introduced by the HTTP server. @@ -53,6 +54,8 @@ type Conn struct { chunking bool; // using chunked transfer encoding for reply body wroteHeader bool; // reply header has been written header map[string] string; // reply header parameters + written int64; // number of bytes written in body + status int; // status code passed to WriteHeader } // Create new connection from rwc. @@ -134,6 +137,8 @@ func (c *Conn) WriteHeader(code int) { return } c.wroteHeader = true; + c.status = code; + c.written = 0; if !c.Req.ProtoAtLeast(1, 0) { return } @@ -168,6 +173,8 @@ func (c *Conn) Write(data []byte) (n int, err os.Error) { return 0, nil } + c.written += int64(len(data)); // ignoring errors, for errorKludge + // TODO(rsc): if chunking happened after the buffering, // then there would be fewer chunk headers. // On the other hand, it would make hijacking more difficult. @@ -187,10 +194,53 @@ func (c *Conn) Write(data []byte) (n int, err os.Error) { return n, err; } +// If this is an error reply (4xx or 5xx) +// and the handler wrote some data explaining the error, +// some browsers (i.e., Chrome, Internet Explorer) +// will show their own error instead unless the error is +// long enough. The minimum lengths used in those +// browsers are in the 256-512 range. +// Pad to 1024 bytes. +func errorKludge(c *Conn, req *Request) { + const min = 1024; + + // Is this an error? + if kind := c.status/100; kind != 4 && kind != 5 { + return; + } + + // Did the handler supply any info? Enough? + if c.written == 0 || c.written >= min { + return; + } + + // Is it text? ("Content-Type" is always in the map) + if s := c.header["Content-Type"]; len(s) < 5 || s[0:5] != "text/" { + return; + } + + // Is it a broken browser? + var msg string; + switch agent := req.UserAgent; { + case strings.Index(agent, "MSIE") >= 0: + msg = "Internet Explorer"; + case strings.Index(agent, "Chrome/") >= 0: + msg = "Chrome"; + default: + return; + } + msg += " would ignore this error page if this text weren't here.\n"; + io.WriteString(c, "\n"); + for c.written < min { + io.WriteString(c, msg); + } +} + func (c *Conn) flush() { if !c.wroteHeader { c.WriteHeader(StatusOK); } + errorKludge(c, c.Req); if c.chunking { io.WriteString(c.buf, "0\r\n"); // trailer key/value pairs, followed by blank line |