diff options
Diffstat (limited to 'doc/codelab/wiki/index.html')
| -rw-r--r-- | doc/codelab/wiki/index.html | 147 |
1 files changed, 71 insertions, 76 deletions
diff --git a/doc/codelab/wiki/index.html b/doc/codelab/wiki/index.html index 107e49f26..c494a3ced 100644 --- a/doc/codelab/wiki/index.html +++ b/doc/codelab/wiki/index.html @@ -1,7 +1,4 @@ -<div class="content"> - -<h1>Writing Web Applications</h1> - +<!-- Codelab: Writing Web Applications --> <h2>Introduction</h2> <p> @@ -243,8 +240,8 @@ import ( "http" ) -func handler(c *http.Conn, r *http.Request) { - fmt.Fprintf(c, "Hi there, I love %s!", r.URL.Path[1:]) +func handler(w http.ResponseWriter, r *http.Request) { + fmt.Fprintf(w, "Hi there, I love %s!", r.URL.Path[1:]) } func main() { @@ -269,12 +266,12 @@ This function will block until the program is terminated. <p> The function <code>handler</code> is of the type <code>http.HandlerFunc</code>. -It takes an <code>http.Conn</code> and <code>http.Request</code> as its -arguments. +It takes an <code>http.ResponseWriter</code> and an <code>http.Request</code> as +its arguments. </p> <p> -An <code>http.Conn</code> is the server end of an HTTP connection; by writing +An <code>http.ResponseWriter</code> value assembles the HTTP server's response; by writing to it, we send data to the HTTP client. </p> @@ -317,10 +314,10 @@ Let's create a handler to view a wiki page: <pre> const lenPath = len("/view/") -func viewHandler(c *http.Conn, r *http.Request) { +func viewHandler(w http.ResponseWriter, r *http.Request) { title := r.URL.Path[lenPath:] p, _ := loadPage(title) - fmt.Fprintf(c, "<h1>%s</h1><div>%s</div>", p.title, p.body) + fmt.Fprintf(w, "<h1>%s</h1><div>%s</div>", p.title, p.body) } </pre> @@ -336,7 +333,7 @@ begin with <code>"/view/"</code>, which is not part of the page title. <p> The function then loads the page data, formats the page with a string of simple -HTML, and writes it to <code>c</code>, the <code>http.Conn</code>. +HTML, and writes it to <code>w</code>, the <code>http.ResponseWriter</code>. </p> <p> @@ -409,13 +406,13 @@ and displays an HTML form. </p> <pre> -func editHandler(c *http.Conn, r *http.Request) { +func editHandler(w http.ResponseWriter, r *http.Request) { title := r.URL.Path[lenPath:] p, err := loadPage(title) if err != nil { p = &page{title: title} } - fmt.Fprintf(c, "<h1>Editing %s</h1>"+ + fmt.Fprintf(w, "<h1>Editing %s</h1>"+ "<form action=\"/save/%s\" method=\"POST\">"+ "<textarea name=\"body\">%s</textarea><br>"+ "<input type=\"submit\" value=\"Save\">"+ @@ -471,14 +468,14 @@ HTML: </p> <pre> -func editHandler(c *http.Conn, r *http.Request) { +func editHandler(w http.ResponseWriter, r *http.Request) { title := r.URL.Path[lenPath:] p, err := loadPage(title) if err != nil { p = &page{title: title} } t, _ := template.ParseFile("edit.html", nil) - t.Execute(p, c) + t.Execute(p, w) } </pre> @@ -491,7 +488,7 @@ The function <code>template.ParseFile</code> will read the contents of The method <code>t.Execute</code> replaces all occurrences of <code>{title}</code> and <code>{body}</code> with the values of <code>p.title</code> and <code>p.body</code>, and writes the resultant -HTML to the <code>http.Conn</code>. +HTML to the <code>http.ResponseWriter</code>. </p> <p> @@ -526,11 +523,11 @@ Modify <code>viewHandler</code> accordingly: </p> <pre> -func viewHandler(c *http.Conn, r *http.Request) { +func viewHandler(w http.ResponseWriter, r *http.Request) { title := r.URL.Path[lenPath:] p, _ := loadPage(title) t, _ := template.ParseFile("view.html", nil) - t.Execute(p, c) + t.Execute(p, w) } </pre> @@ -541,24 +538,24 @@ to its own function: </p> <pre> -func viewHandler(c *http.Conn, r *http.Request) { +func viewHandler(w http.ResponseWriter, r *http.Request) { title := r.URL.Path[lenPath:] p, _ := loadPage(title) - renderTemplate(c, "view", p) + renderTemplate(w, "view", p) } -func editHandler(c *http.Conn, r *http.Request) { +func editHandler(w http.ResponseWriter, r *http.Request) { title := r.URL.Path[lenPath:] p, err := loadPage(title) if err != nil { p = &page{title: title} } - renderTemplate(c, "edit", p) + renderTemplate(w, "edit", p) } -func renderTemplate(c *http.Conn, tmpl string, p *page) { +func renderTemplate(w http.ResponseWriter, tmpl string, p *page) { t, _ := template.ParseFile(tmpl+".html", nil) - t.Execute(p, c) + t.Execute(p, w) } </pre> @@ -576,13 +573,13 @@ redirect the client to the edit page so the content may be created: </p> <pre> -func viewHandler(c *http.Conn, r *http.Request, title string) { +func viewHandler(w http.ResponseWriter, r *http.Request, title string) { p, err := loadPage(title) if err != nil { - http.Redirect(c, "/edit/"+title, http.StatusFound) + http.Redirect(w, r, "/edit/"+title, http.StatusFound) return } - renderTemplate(c, "view", p) + renderTemplate(w, "view", p) } </pre> @@ -599,12 +596,12 @@ The function <code>saveHandler</code> will handle the form submission. </p> <pre> -func saveHandler(c *http.Conn, r *http.Request) { +func saveHandler(w http.ResponseWriter, r *http.Request) { title := r.URL.Path[lenPath:] body := r.FormValue("body") p := &page{title: title, body: []byte(body)} p.save() - http.Redirect(c, "/view/"+title, http.StatusFound) + http.Redirect(w, r, "/view/"+title, http.StatusFound) } </pre> @@ -637,15 +634,15 @@ First, let's handle the errors in <code>renderTemplate</code>: </p> <pre> -func renderTemplate(c *http.Conn, tmpl string, p *page) { +func renderTemplate(w http.ResponseWriter, tmpl string, p *page) { t, err := template.ParseFile(tmpl+".html", nil) if err != nil { - http.Error(c, err.String(), http.StatusInternalServerError) + http.Error(w, err.String(), http.StatusInternalServerError) return } - err = t.Execute(p, c) + err = t.Execute(p, w) if err != nil { - http.Error(c, err.String(), http.StatusInternalServerError) + http.Error(w, err.String(), http.StatusInternalServerError) } } </pre> @@ -661,15 +658,15 @@ Now let's fix up <code>saveHandler</code>: </p> <pre> -func saveHandler(c *http.Conn, r *http.Request, title string) { +func saveHandler(w http.ResponseWriter, r *http.Request, title string) { body := r.FormValue("body") p := &page{title: title, body: []byte(body)} err := p.save() if err != nil { - http.Error(c, err.String(), http.StatusInternalServerError) + http.Error(w, err.String(), http.StatusInternalServerError) return } - http.Redirect(c, "/view/"+title, http.StatusFound) + http.Redirect(w, r, "/view/"+title, http.StatusFound) } </pre> @@ -728,10 +725,10 @@ the <code>Execute</code> method on the appropriate <code>Template</code> from <code>templates</code>: <pre> -func renderTemplate(c *http.Conn, tmpl string, p *page) { - err := templates[tmpl].Execute(p, c) +func renderTemplate(w http.ResponseWriter, tmpl string, p *page) { + err := templates[tmpl].Execute(p, w) if err != nil { - http.Error(c, err.String(), http.StatusInternalServerError) + http.Error(w, err.String(), http.StatusInternalServerError) } } </pre> @@ -768,10 +765,10 @@ URL, and tests it against our <code>titleValidator</code> expression: </p> <pre> -func getTitle(c *http.Conn, r *http.Request) (title string, err os.Error) { +func getTitle(w http.ResponseWriter, r *http.Request) (title string, err os.Error) { title = r.URL.Path[lenPath:] if !titleValidator.MatchString(title) { - http.NotFound(c, r) + http.NotFound(w, r) err = os.NewError("Invalid Page Title") } return @@ -790,21 +787,21 @@ Let's put a call to <code>getTitle</code> in each of the handlers: </p> <pre> -func viewHandler(c *http.Conn, r *http.Request) { - title, err := getTitle(c, r) +func viewHandler(w http.ResponseWriter, r *http.Request) { + title, err := getTitle(w, r) if err != nil { return } p, err := loadPage(title) if err != nil { - http.Redirect(c, "/edit/"+title, http.StatusFound) + http.Redirect(w, r, "/edit/"+title, http.StatusFound) return } - renderTemplate(c, "view", p) + renderTemplate(w, "view", p) } -func editHandler(c *http.Conn, r *http.Request) { - title, err := getTitle(c, r) +func editHandler(w http.ResponseWriter, r *http.Request) { + title, err := getTitle(w, r) if err != nil { return } @@ -812,11 +809,11 @@ func editHandler(c *http.Conn, r *http.Request) { if err != nil { p = &page{title: title} } - renderTemplate(c, "edit", p) + renderTemplate(w, "edit", p) } -func saveHandler(c *http.Conn, r *http.Request) { - title, err := getTitle(c, r) +func saveHandler(w http.ResponseWriter, r *http.Request) { + title, err := getTitle(w, r) if err != nil { return } @@ -824,10 +821,10 @@ func saveHandler(c *http.Conn, r *http.Request) { p := &page{title: title, body: []byte(body)} err = p.save() if err != nil { - http.Error(c, err.String(), http.StatusInternalServerError) + http.Error(w, err.String(), http.StatusInternalServerError) return } - http.Redirect(c, "/view/"+title, http.StatusFound) + http.Redirect(w, r, "/view/"+title, http.StatusFound) } </pre> @@ -848,9 +845,9 @@ a title string: </p> <pre> -func viewHandler(c *http.Conn, r *http.Request, title string) -func editHandler(c *http.Conn, r *http.Request, title string) -func saveHandler(c *http.Conn, r *http.Request, title string) +func viewHandler(w http.ResponseWriter, r *http.Request, title string) +func editHandler(w http.ResponseWriter, r *http.Request, title string) +func saveHandler(w http.ResponseWriter, r *http.Request, title string) </pre> <p> @@ -860,8 +857,8 @@ type</i>, and returns a function of type <code>http.HandlerFunc</code> </p> <pre> -func makeHandler(fn func (*http.Conn, *http.Request, string)) http.HandlerFunc { - return func(c *http.Conn, r *http.Request) { +func makeHandler(fn func (http.ResponseWriter, *http.Request, string)) http.HandlerFunc { + return func(w http.ResponseWriter, r *http.Request) { // Here we will extract the page title from the Request, // and call the provided handler 'fn' } @@ -881,28 +878,28 @@ Now we can take the code from <code>getTitle</code> and use it here </p> <pre> -func makeHandler(fn func(*http.Conn, *http.Request, string)) http.HandlerFunc { - return func(c *http.Conn, r *http.Request) { +func makeHandler(fn func(http.ResponseWriter, *http.Request, string)) http.HandlerFunc { + return func(w http.ResponseWriter, r *http.Request) { title := r.URL.Path[lenPath:] if !titleValidator.MatchString(title) { - http.NotFound(c, r) + http.NotFound(w, r) return } - fn(c, r, title) + fn(w, r, title) } } </pre> <p> The closure returned by <code>makeHandler</code> is a function that takes -an <code>http.Conn</code> and <code>http.Request</code> (in other words, -an <code>http.HandlerFunc</code>). +an <code>http.ResponseWriter</code> and <code>http.Request</code> (in other +words, an <code>http.HandlerFunc</code>). The closure extracts the <code>title</code> from the request path, and validates it with the <code>titleValidator</code> regexp. If the <code>title</code> is invalid, an error will be written to the -<code>Conn</code> using the <code>http.NotFound</code> function. +<code>ResponseWriter</code> using the <code>http.NotFound</code> function. If the <code>title</code> is valid, the enclosed handler function -<code>fn</code> will be called with the <code>Conn</code>, +<code>fn</code> will be called with the <code>ResponseWriter</code>, <code>Request</code>, and <code>title</code> as arguments. </p> @@ -927,32 +924,32 @@ making them much simpler: </p> <pre> -func viewHandler(c *http.Conn, r *http.Request, title string) { +func viewHandler(w http.ResponseWriter, r *http.Request, title string) { p, err := loadPage(title) if err != nil { - http.Redirect(c, "/edit/"+title, http.StatusFound) + http.Redirect(w, r, "/edit/"+title, http.StatusFound) return } - renderTemplate(c, "view", p) + renderTemplate(w, "view", p) } -func editHandler(c *http.Conn, r *http.Request, title string) { +func editHandler(w http.ResponseWriter, r *http.Request, title string) { p, err := loadPage(title) if err != nil { p = &page{title: title} } - renderTemplate(c, "edit", p) + renderTemplate(w, "edit", p) } -func saveHandler(c *http.Conn, r *http.Request, title string) { +func saveHandler(w http.ResponseWriter, r *http.Request, title string) { body := r.FormValue("body") p := &page{title: title, body: []byte(body)} err := p.save() if err != nil { - http.Error(c, err.String(), http.StatusInternalServerError) + http.Error(w, err.String(), http.StatusInternalServerError) return } - http.Redirect(c, "/view/"+title, http.StatusFound) + http.Redirect(w, r, "/view/"+title, http.StatusFound) } </pre> @@ -996,5 +993,3 @@ Here are some simple tasks you might want to tackle on your own: (hint: you could use <code>regexp.ReplaceAllFunc</code> to do this) </li> </ul> - -</div> |