/
app.go
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/
app.go
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package web
import (
"bytes"
"fmt"
"http"
"io"
"log"
"os"
"strings"
)
// Internal used logger.
var logger *log.Logger
func init() {
logFile, _ := os.Open("/tmp/ds.web.log", os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0600)
logger = log.New(logFile, "", log.Lshortfile|log.Ltime)
}
//func SetLogger()
const (
PathMatchedNothing = 0
PathMatchedFull = 1 // the paths matched exactly
PathMatchedParent = 2 // both paths has the same parent: /edit, /edit/1, /edit/2
)
// RequestHandler make response to a request.
type RequestHandler interface {
HandleRequest(request *Request, response *Response) (err os.Error)
}
// SubpathHandler handle subpath requests.
type SubpathHandler interface {
HandleSubpath(subpath string, request *Request) bool
}
// FuncHandler is used to wrap a typical func as a web.RequestHandler.
type FuncHandler func(request *Request, response *Response) (err os.Error)
// Manage persistent multiple requests.
type RequestManager interface {
GetRequest(id string) (request *Request, err os.Error)
ProcessRequest(req *Request) (response *Response, err os.Error)
}
// Indicate a model of a app, e.g. CGIModel, FCGIModel, SCGIModel, etc.
type AppModel interface {
ProcessRequests(rp RequestManager) os.Error
}
// Request derived from http.Request and represents the web request.
type Request struct {
http.Request
Path string
ScriptName string
QueryString string
HttpCookie string
app *App
cookies []*Cookie
query map[string][]string // parsed query
}
// Response derived from http.Response and represents the web response.
type Response struct {
http.Response
BodyWriter io.Writer
app *App
cookies []*Cookie
}
// Cookie represents the http cookies.
type Cookie struct {
Name string
Content string // TODO: should be named as Value
Domain string
Path string
Expires string
Version string
}
// Indicate a CGI web session, also holds parameters of a request.
type App struct {
model AppModel
handlers map[string]RequestHandler
pathMatcher PathMatcher
requests map[string]*Request
}
// Responsible for checking two paths to see if they are identical.
// TODO: think about paths like '/edit/*'
type PathMatcher interface {
PathMatch(p1 string, p2 string) (n int, sub string)
}
// The default method of matching two path: matched if equal
type DefaultPathMatcher int
// RegexPathMatcher match paths using regex expression.
type RegexPathMatcher int
func (f FuncHandler) HandleRequest(request *Request, response *Response) (err os.Error) {
return f(request, response)
}
func (request *Request) Cookies() []*Cookie { return request.cookies }
func (request *Request) Cookie(k string) (rc *Cookie) {
for _, c := range request.cookies {
if c.Name == k {
rc = c
}
}
return
}
func (c *Cookie) String() string {
s := ""
if c.Name != "" { s += c.Name + "=" + c.Content }
if c.Expires != "" { s += "; expires=" + c.Expires }
if c.Domain != "" { s += "; domain=" + c.Domain }
if c.Path != "" { s += "; path=" + c.Path }
if c.Version != "" { s += "; version=" + c.Version }
return s
}
// Parse http cookies header.
// See http://ftp.ics.uci.edu/pub/ietf/http/rfc2109.txt for full spec.
func ParseCookies(s string) (cookies []*Cookie) {
cookies = make([]*Cookie, 0, 5)
s = strings.TrimSpace(s) // FIXME: needed?
if ss := strings.Split(s, ";", -1); 0 < len(ss) {
var c *Cookie
for _, a := range ss {
kv := strings.Split(strings.TrimSpace(a), "=", 2)
if len(kv) != 2 { continue }
switch kv[0] {
case "$Version":
// TODO: version checking
continue
case "$Domain":
if c != nil { c.Domain = kv[1] }
case "$Path":
if c != nil { c.Path = kv[1] }
case "$Max-Age":
if c != nil { /* TODO: Max-Age selection... */ }
default:
c = new(Cookie)
c.Name = kv[0]
c.Content = kv[1]
cookies = append(cookies, c)
c = nil // reset
}
}
}
return
}
// Create a new web.App to talk to a http session.
func NewApp(m interface {}) (app *App, err os.Error) {
if m == nil {
err = newError("web.NewApp: Invalid parameter!")
return
}
switch v := m.(type) {
case AppModel:
app = new(App)
err = app.initFromModel(v)
if err != nil { app = nil }
}
return
}
func (app *App) initFromModel(am AppModel) (err os.Error) {
app.model = am
app.handlers = make(map[string]RequestHandler)
app.pathMatcher = DefaultPathMatcher(PathMatchedNothing)
app.requests = make(map[string]*Request)
return
}
func (app *App) GetModel() AppModel { return app.model }
func (app *App) Handle(url string, h RequestHandler) (prev RequestHandler) {
prev = app.handlers[url]
app.handlers[url] = h
return
}
func (app *App) HandleDefault(h RequestHandler) (prev RequestHandler) {
prev = app.handlers[""]
app.handlers[""] = h
if app.handlers["/"] == nil {
app.handlers["/"] = h
}
return
}
func (app *App) ReturnError(w io.Writer, err interface{}) {
fmt.Fprintf(w, "Content-Type: text/plain\n\n")
fmt.Fprintf(w, "error: %v", err)
}
func (res *Response) writeHeader(w io.Writer) (err os.Error) {
for _, v := range res.cookies {
fmt.Fprintf(w, "Set-Cookie: %s\n", v.String())
}
for k, v := range res.Header { // map[string][]string
for _, vi := range v {
fmt.Fprintf(w, "%s: %s\n", k, vi)
}
}
fmt.Fprintf(w, "\n")
return
}
func (app *App) Exec() (err os.Error) {
err = app.model.ProcessRequests(app)
if err != nil {
// ....
}
return
}
func (app *App) GetRequest(id string) (request *Request, err os.Error) {
// TODO: multiple requests management
var found bool
request, found = app.requests[id]
if !found || request == nil {
request = &Request{}
app.requests[id] = request
}
request.app = app
return
}
type noCloseReader struct { io.Reader }
func (c noCloseReader) Close() os.Error { return nil }
// Process a single incoming request.
func (app *App) ProcessRequest(req *Request) (response *Response, err os.Error) {
req.query, err = http.ParseQuery(req.QueryString)
if err != nil {
/* TODO: log error */
return
}
contentBuffer := bytes.NewBuffer(make([]byte, 1024*10))
contentBuffer.Reset()
response = &Response{}
response.app = app
response.cookies = make([]*Cookie, 0, 8)
response.Header = http.Header(make(map[string][]string))
response.Body = noCloseReader{ contentBuffer }
response.BodyWriter = contentBuffer
handled := false
for k, h := range app.handlers {
if m, s := app.pathMatcher.PathMatch(k, req.Path); m != PathMatchedNothing {
if m == PathMatchedParent {
sh, ok := h.(SubpathHandler)
if ok && !sh.HandleSubpath(s, req) {
continue
}
}
err = h.HandleRequest(req, response)
if err != nil {
// TODO: error handling...
return
}
response.ContentLength = int64(contentBuffer.Len())
handled = true
break // just ignore any other handlers
}
}//for (app.handlers)
if !handled {
contentBuffer.Reset()
w := contentBuffer
fmt.Fprintf(w, "Content-Type: text/html; charset=utf-8\n\n")
fmt.Fprintf(w, `<html>`)
fmt.Fprintf(w, `<head>`)
fmt.Fprintf(w, `<meta http-equiv="content-type" content="text/html;charset=utf-8">`)
fmt.Fprintf(w, `</head>`)
fmt.Fprintf(w, `<body>`)
fmt.Fprintf(w, `<font color="red"><h1>Error: 404</h1></font>`)
fmt.Fprintf(w, `The requested URL <code>%s%s</code> was not found on this server`, req.ScriptName, req.Path)
fmt.Fprintf(w, `<body>`)
fmt.Fprintf(w, `</html>`)
}
return
}
func (m DefaultPathMatcher) PathMatch(p1 string, p2 string) (n int, sub string) {
n = PathMatchedNothing
if len(p1) <= len(p2) {
pre := p2[0:len(p1)]
if pre != p1 { /* matched nothing */ return }
l := len(p2)-len(p1)
if l == 0 {
n = PathMatchedFull
} else {
n = PathMatchedParent
// For cases of: p1(/) <=> p2(/sync),
// p1(/buy/a/) <=> p2(/buy/a/1)
if len(p1) == 0 || p1[len(p1)-1:len(p1)] == "/" { sub = "/" }
sub += p2[len(p1):len(p1)+l]
}
}
return
}
func (m RegexPathMatcher) PathMatch(p1 string, p2 string) (n int, sub string) {
// TODO: implement this...
return
}