early HTTP library and trivial server

R=r
OCL=15777
CL=15791

1 files changed, 300 insertions, 0 deletions

diff --git a/src/lib/http/request.go b/src/lib/http/request.go
new file mode 100644
index 000000000..bed911eb4
--- /dev/null
+++ b/src/lib/http/request.go
@@ -0,0 +1,300 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// HTTP Request reading and parsing.
+
+package http
+
+import (
+	"bufio";
+	"http";
+	"os";
+	"strings"
+)
+
+const (
+	MaxLineLength = 1024;	// assumed < bufio.DefaultBufSize
+	MaxValueLength = 1024;
+	MaxHeaderLines = 1024;
+)
+
+export var (
+	LineTooLong = os.NewError("http header line too long");
+	ValueTooLong = os.NewError("http header value too long");
+	HeaderTooLong = os.NewError("http header too long");
+	BadHeader = os.NewError("malformed http header");
+	BadRequest = os.NewError("invalid http request");
+	BadHTTPVersion = os.NewError("unsupported http version");
+)
+
+// HTTP Request
+export type Request struct {
+	method string;		// GET, PUT,etc.
+	rawurl string;
+	url *URL;		// URI after GET, PUT etc.
+	proto string;	// "HTTP/1.0"
+	pmajor int;	// 1
+	pminor int;	// 0
+
+	header *map[string] string;
+
+	close bool;
+	host string;
+	referer string;
+	useragent string;
+}
+
+// Read a line of bytes (up to \n) from b.
+// Give up if the line exceeds MaxLineLength.
+// The returned bytes are a pointer into storage in
+// the bufio, so they are only valid until the next bufio read.
+func ReadLineBytes(b *bufio.BufRead) (p *[]byte, err *os.Error) {
+	if p, err = b.ReadLineSlice('\n'); err != nil {
+		return nil, err
+	}
+	if len(p) >= MaxLineLength {
+		return nil, LineTooLong
+	}
+
+	// Chop off trailing white space.
+	var i int
+	for i = len(p); i > 0; i-- {
+		if c := p[i-1]; c != ' ' && c != '\r' && c != '\t' && c != '\n' {
+			break
+		}
+	}
+	return p[0:i], nil
+}
+
+// ReadLineByte, but convert the bytes into a string.
+func ReadLine(b *bufio.BufRead) (s string, err *os.Error) {
+	p, e := ReadLineBytes(b)
+	if e != nil {
+		return "", e
+	}
+	return string(p), nil
+}
+
+// Read a key/value pair from b.
+// A key/value has the form Key: Value\r\n
+// and the Value can continue on multiple lines if each continuation line
+// starts with a space.
+func ReadKeyValue(b *bufio.BufRead) (key, value string, err *os.Error) {
+	line, e := ReadLineBytes(b)
+	if e != nil {
+		return "", "", e
+	}
+	if len(line) == 0 {
+		return "", "", nil
+	}
+
+	// Scan first line for colon.
+	for i := 0; i < len(line); i++ {
+		switch line[i] {
+		case ' ':
+			// Key field has space - no good.
+			return "", "", BadHeader
+		case ':':
+			key = string(line[0:i]);
+			// Skip initial space before value.
+			for i++; i < len(line); i++ {
+				if line[i] != ' ' {
+					break
+				}
+			}
+			value = string(line[i:len(line)])
+
+			// Look for extension lines, which must begin with space.
+			for {
+				var c byte;
+
+				if c, e = b.ReadByte(); e != nil {
+					return "", "", e
+				}
+				if c != ' ' {
+					// Not leading space; stop.
+					b.UnreadByte()
+					break
+				}
+
+				// Eat leading space.
+				for c == ' ' {
+					if c, e = b.ReadByte(); e != nil {
+						return "", "", e
+					}
+				}
+				b.UnreadByte()
+
+				// Read the rest of the line and add to value.
+				if line, e = ReadLineBytes(b); e != nil {
+					return "", "", e
+				}
+				value += " " + string(line)
+
+				if len(value) >= MaxValueLength {
+					return "", "", ValueTooLong
+				}
+			}
+			return key, value, nil
+		}
+	}
+
+	// Line ended before space or colon.
+	return "", "", BadHeader;
+}
+
+// Convert decimal at s[i:len(s)] to integer,
+// returning value, string position where the digits stopped,
+// and whether there was a valid number (digits, not too big).
+func atoi(s string, i int) (n, i1 int, ok bool) {
+	const Big = 1000000
+	if i >= len(s) || s[i] < '0' || s[i] > '9' {
+		return 0, 0, false
+	}
+	n = 0
+	for ; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ {
+		n = n*10 + int(s[i]-'0')
+		if n > Big {
+			return 0, 0, false
+		}
+	}
+	return n, i, true
+}
+
+// Parse HTTP version: "HTTP/1.2" -> (1, 2, true).
+func ParseHTTPVersion(vers string) (int, int, bool) {
+	if vers[0:5] != "HTTP/" {
+		return 0, 0, false
+	}
+	major, i, ok := atoi(vers, 5)
+	if !ok || i >= len(vers) || vers[i] != '.' {
+		return 0, 0, false
+	}
+	var minor int;
+	minor, i, ok = atoi(vers, i+1)
+	if !ok || i != len(vers) {
+		return 0, 0, false
+	}
+	return major, minor, true
+}
+
+// Read and parse a request from b.
+export func ReadRequest(b *bufio.BufRead) (req *Request, err *os.Error) {
+	req = new(Request);
+
+	// First line: GET /index.html HTTP/1.0
+	var s string
+	if s, err = ReadLine(b); err != nil {
+		return nil, err
+	}
+
+	var f *[]string
+	if f = strings.split(s, " "); len(f) != 3 {
+		return nil, BadRequest
+	}
+	req.method, req.rawurl, req.proto = f[0], f[1], f[2]
+	var ok bool;
+	if req.pmajor, req.pminor, ok = ParseHTTPVersion(req.proto); !ok {
+		return nil, BadHTTPVersion
+	}
+
+	if req.url, err = ParseURL(req.rawurl); err != nil {
+		return nil, err
+	}
+
+	// Subsequent lines: Key: value.
+	nheader := 0;
+	req.header = new(map[string] string)
+	for {
+		var key, value string
+		if key, value, err = ReadKeyValue(b); err != nil {
+			return nil, err
+		}
+		if key == "" {
+			break
+		}
+		if nheader++; nheader >= MaxHeaderLines {
+			return nil, HeaderTooLong
+		}
+
+		// RFC 2616 says that if you send the same header key
+		// multiple times, it has to be semantically equivalent
+		// to concatenating the values separated by commas.
+		oldvalue, present := req.header[key]
+		if present {
+			req.header[key] = oldvalue+","+value
+		} else {
+			req.header[key] = value
+		}
+	}
+
+	// RFC2616: Must treat
+	//	GET /index.html HTTP/1.1
+	//	Host: www.google.com
+	// and
+	//	GET http://www.google.com/index.html HTTP/1.1
+	//	Host: doesntmatter
+	// the same.  In the second case, any Host line is ignored.
+	if v, have := req.header["Host"]; have && req.url.host == "" {
+		req.host = v
+	}
+
+	// RFC2616: Should treat
+	//	Pragma: no-cache
+	// like
+	//	Cache-control: no-cache
+	if v, have := req.header["Pragma"]; have && v == "no-cache" {
+		if cc, havecc := req.header["Cache-control"]; !havecc {
+			req.header["Cache-control"] = "no-cache"
+		}
+	}
+
+	// Determine whether to hang up after sending the reply.
+	if req.pmajor < 1 || (req.pmajor == 1 && req.pminor < 1) {
+		req.close = true
+	} else if v, have := req.header["Connection"]; have {
+		// TODO: Should split on commas, toss surrounding white space,
+		// and check each field.
+		if v == "close" {
+			req.close = true
+		}
+	}
+
+	// Pull out useful fields as a convenience to clients.
+	if v, have := req.header["Referer"]; have {
+		req.referer = v
+	}
+	if v, have := req.header["User-Agent"]; have {
+		req.useragent = v
+	}
+
+
+	// TODO: Parse specific header values:
+	//	Accept
+	//	Accept-Encoding
+	//	Accept-Language
+	//	Authorization
+	//	Cache-Control
+	//	Connection
+	//	Date
+	//	Expect
+	//	From
+	//	If-Match
+	//	If-Modified-Since
+	//	If-None-Match
+	//	If-Range
+	//	If-Unmodified-Since
+	//	Max-Forwards
+	//	Proxy-Authorization
+	//	Referer [sic]
+	//	TE (transfer-codings)
+	//	Trailer
+	//	Transfer-Encoding
+	//	Upgrade
+	//	User-Agent
+	//	Via
+	//	Warning
+
+	return req, nil;
+}