完成第十三章的书写
This commit is contained in:
xiemengjun
499
13.5.md
499
13.5.md
@@ -1,248 +1,259 @@
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# 13.5 日志和配置设计
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## 日志和配置的重要性
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前面已经介绍过日志在我们程序开发中起着很重要的作用，通过日志我们可以记录调试我们的信息，当初介绍过一个日志系统seelog，根据不同的level输出不同的日志，这个对于程序开发和程序部署来说至关重要。我们可以在程序开发中设置level低一点，部署的时候把level设置高，这样我们开发中的调试信息可以屏蔽掉。
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配置模块对于应用部署牵涉到服务器不同的一些配置信息非常有用，例如一些数据库配置信息、监听端口、监听地址等都是可以通过配置文件来配置，这样我们的应用程序就具有很强的灵活性，可以通过配置文件的配置部署在不同的机器上，可以连接不同的数据库之类的。
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## beego的日志设计
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beego的日志设计部署思路来自于seelog，根据不同的level来记录日志，但是beego设计的日志系统比较轻量级，采用了系统的log.Logger接口，默认输出到os.Stdout,用户可以实现这个接口然后通过beego.SetLogger设置自定义的输出，详细的实现如下所示：
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// Log levels to control the logging output.
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const (
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LevelTrace = iota
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LevelDebug
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LevelInfo
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LevelWarning
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LevelError
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LevelCritical
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)
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// logLevel controls the global log level used by the logger.
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var level = LevelTrace
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// LogLevel returns the global log level and can be used in
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// own implementations of the logger interface.
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func Level() int {
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return level
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}
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// SetLogLevel sets the global log level used by the simple
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// logger.
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func SetLevel(l int) {
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level = l
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}
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上面这一段实现了日志系统的日志分级，默认的级别是Trace，用户通过SetLevel可以设置不同的分级。
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// logger references the used application logger.
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var BeeLogger = log.New(os.Stdout, "", log.Ldate|log.Ltime)
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// SetLogger sets a new logger.
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func SetLogger(l *log.Logger) {
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BeeLogger = l
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}
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// Trace logs a message at trace level.
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func Trace(v ...interface{}) {
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if level <= LevelTrace {
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BeeLogger.Printf("[T] %v\n", v)
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}
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}
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// Debug logs a message at debug level.
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func Debug(v ...interface{}) {
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if level <= LevelDebug {
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BeeLogger.Printf("[D] %v\n", v)
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}
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}
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// Info logs a message at info level.
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func Info(v ...interface{}) {
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if level <= LevelInfo {
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BeeLogger.Printf("[I] %v\n", v)
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}
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}
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// Warning logs a message at warning level.
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func Warn(v ...interface{}) {
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if level <= LevelWarning {
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BeeLogger.Printf("[W] %v\n", v)
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}
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}
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// Error logs a message at error level.
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func Error(v ...interface{}) {
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if level <= LevelError {
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BeeLogger.Printf("[E] %v\n", v)
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}
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}
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// Critical logs a message at critical level.
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func Critical(v ...interface{}) {
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if level <= LevelCritical {
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BeeLogger.Printf("[C] %v\n", v)
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}
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}
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上面这一段代码默认初始化了一个BeeLogger对象，默认输出到os.Stdout，用户可以通过beego.SetLogger来设置实现了logger的接口输出。这里面实现了六个函数：
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- Trace（一般的记录信息，举例如下：）
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- "Entered parse function validation block"
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- "Validation: entered second 'if'"
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- "Dictionary 'Dict' is empty. Using default value"
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- Debug（调试信息，举例如下：）
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- "Web page requested: http://somesite.com Params='...'"
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- "Response generated. Response size: 10000. Sending."
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- "New file received. Type:PNG Size:20000"
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- Info（打印信息，举例如下：）
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- "Web server restarted"
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- "Hourly statistics: Requested pages: 12345 Errors: 123 ..."
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- "Service paused. Waiting for 'resume' call"
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- Warn（警告信息，举例如下：）
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- "Cache corrupted for file='test.file'. Reading from back-end"
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- "Database 192.168.0.7/DB not responding. Using backup 192.168.0.8/DB"
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- "No response from statistics server. Statistics not sent"
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- Error（错误信息，举例如下：）
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- "Internal error. Cannot process request #12345 Error:...."
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- "Cannot perform login: credentials DB not responding"
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- Critical（致命错误，举例如下：）
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- "Critical panic received: .... Shutting down"
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- "Fatal error: ... App is shutting down to prevent data corruption or loss"
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可以看到每个函数里面都有对level的判断，所以如果我们在部署的时候设置了level=LevelWarning，那么Trace、Debug、Info这三个函数都不会有任何的输出，以此类推。
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## beego的配置设计
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配置信息的解析，beego实现了一个key=value的配置文件读取，类似ini配置文件的格式，就是一个文件解析的过程，然后把解析的数据保存到map中，最后在调用的时候通过几个string、int之类的函数调用返回相应的值，具体的实现请看下面：
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首先定义了一些ini配置文件的一些全局性常量 ：
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var (
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bComment = []byte{'#'}
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bEmpty = []byte{}
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bEqual = []byte{'='}
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bDQuote = []byte{'"'}
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)
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定义了配置文件的格式：
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// A Config represents the configuration.
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type Config struct {
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filename string
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comment map[int][]string // id: []{comment, key...}; id 1 is for main comment.
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data map[string]string // key: value
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offset map[string]int64 // key: offset; for editing.
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sync.RWMutex
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}
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定义了解析文件的函数，解析文件的过程是打开文件，然后一行一行的读取，解析注释、空行和key=value数据：
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// ParseFile creates a new Config and parses the file configuration from the
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// named file.
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func LoadConfig(name string) (*Config, error) {
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file, err := os.Open(name)
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if err != nil {
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return nil, err
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}
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cfg := &Config{
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file.Name(),
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make(map[int][]string),
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make(map[string]string),
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make(map[string]int64),
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sync.RWMutex{},
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}
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cfg.Lock()
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defer cfg.Unlock()
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defer file.Close()
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var comment bytes.Buffer
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buf := bufio.NewReader(file)
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for nComment, off := 0, int64(1); ; {
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line, _, err := buf.ReadLine()
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if err == io.EOF {
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break
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}
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if bytes.Equal(line, bEmpty) {
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continue
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}
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off += int64(len(line))
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if bytes.HasPrefix(line, bComment) {
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line = bytes.TrimLeft(line, "#")
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line = bytes.TrimLeftFunc(line, unicode.IsSpace)
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comment.Write(line)
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comment.WriteByte('\n')
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continue
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}
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if comment.Len() != 0 {
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cfg.comment[nComment] = []string{comment.String()}
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comment.Reset()
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nComment++
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}
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val := bytes.SplitN(line, bEqual, 2)
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if bytes.HasPrefix(val[1], bDQuote) {
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val[1] = bytes.Trim(val[1], `"`)
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}
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key := strings.TrimSpace(string(val[0]))
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cfg.comment[nComment-1] = append(cfg.comment[nComment-1], key)
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cfg.data[key] = strings.TrimSpace(string(val[1]))
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cfg.offset[key] = off
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}
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return cfg, nil
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}
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下面实现了一些读取配置文件的函数，返回的值确定为bool、int、float64或string：
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// Bool returns the boolean value for a given key.
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func (c *Config) Bool(key string) (bool, error) {
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return strconv.ParseBool(c.data[key])
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}
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// Int returns the integer value for a given key.
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func (c *Config) Int(key string) (int, error) {
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return strconv.Atoi(c.data[key])
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}
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// Float returns the float value for a given key.
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func (c *Config) Float(key string) (float64, error) {
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return strconv.ParseFloat(c.data[key], 64)
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}
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// String returns the string value for a given key.
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func (c *Config) String(key string) string {
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return c.data[key]
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}
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## 应用指南
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下面这个函数是我一个应用中的例子，用来获取远程url地址的json数据，实现如下：
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func GetJson() {
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resp, err := http.Get(beego.AppConfig.String("url"))
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if err != nil {
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beego.Critical("http get info error")
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return
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}
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defer resp.Body.Close()
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body, err := ioutil.ReadAll(resp.Body)
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err = json.Unmarshal(body, &AllInfo)
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if err != nil {
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beego.Critical("error:", err)
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}
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}
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函数中调用了框架的日志函数`beego.Critical`函数用来报错，调用了`beego.AppConfig.String("url")`用来获取配置文件中的信息，配置文件的信息如下(app.conf)：
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appname = hs
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url ="http://www.api.com/api.html"
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# 13.5 实现博客的增删改
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前面介绍了beego框架实现的整体构思以及部分实现的伪代码，这小节介绍通过beego建立一个博客系统，包括博客浏览、添加、修改、删除等操作。
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## 博客目录
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博客目录如下所示：
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/main.go
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/views:
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/view.tpl
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/new.tpl
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/layout.tpl
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/index.tpl
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/edit.tpl
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/models/model.go
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/controllers:
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/index.go
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/view.go
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/new.go
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/delete.go
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/edit.go
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## 博客路由
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博客主要的路由规则如下所示：
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//显示博客首页
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beego.RegisterController("/", &controllers.IndexController{})
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//查看博客详细信息
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beego.RegisterController("/view/:id([0-9]+)", &controllers.ViewController{})
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//新建博客博文
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beego.RegisterController("/new", &controllers.NewController{})
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//删除博文
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beego.RegisterController("/delete/:id([0-9]+)", &controllers.DeleteController{})
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//编辑博文
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beego.RegisterController("/edit/:id([0-9]+)", &controllers.EditController{})
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## 数据库结构
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数据库设计最简单的博客信息
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CREATE TABLE entries (
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id INT AUTO_INCREMENT,
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title TEXT,
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content TEXT,
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created DATETIME,
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primary key (id)
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);
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## 控制器
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IndexController:
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type IndexController struct {
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beego.Controller
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}
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func (this *IndexController) Get() {
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this.Data["blogs"] = models.GetAll()
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this.Layout = "layout.tpl"
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this.TplNames = "index.tpl"
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}
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ViewController:
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type ViewController struct {
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beego.Controller
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}
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func (this *ViewController) Get() {
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inputs := this.Input()
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id, _ := strconv.Atoi(this.Ctx.Params[":id"])
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this.Data["Post"] = models.GetBlog(id)
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this.Layout = "layout.tpl"
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this.TplNames = "view.tpl"
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}
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NewController
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type NewController struct {
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beego.Controller
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}
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func (this *NewController) Get() {
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this.Layout = "layout.tpl"
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this.TplNames = "new.tpl"
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}
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func (this *NewController) Post() {
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inputs := this.Input()
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var blog models.Blog
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blog.Title = inputs.Get("title")
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blog.Content = inputs.Get("content")
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blog.Created = time.Now()
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models.SaveBlog(blog)
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this.Ctx.Redirect(302, "/")
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}
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EditController
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type EditController struct {
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beego.Controller
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}
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func (this *EditController) Get() {
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inputs := this.Input()
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id, _ := strconv.Atoi(this.Ctx.Params[":id"])
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this.Data["Post"] = models.GetBlog(id)
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this.Layout = "layout.tpl"
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this.TplNames = "new.tpl"
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}
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func (this *EditController) Post() {
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inputs := this.Input()
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var blog models.Blog
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blog.Id, _ = strconv.Atoi(inputs.Get("id"))
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blog.Title = inputs.Get("title")
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blog.Content = inputs.Get("content")
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blog.Created = time.Now()
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models.SaveBlog(blog)
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this.Ctx.Redirect(302, "/")
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}
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DeleteController
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type DeleteController struct {
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beego.Controller
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}
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func (this *DeleteController) Get() {
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inputs := this.Input()
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id, _ := strconv.Atoi(this.Ctx.Params[":id"])
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this.Data["Post"] = models.DelBlog(id)
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this.Ctx.Redirect(302, "/")
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}
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## model层
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package models
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import (
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"database/sql"
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"github.com/astaxie/beedb"
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_ "github.com/ziutek/mymysql/godrv"
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"time"
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)
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type Blog struct {
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Id int `PK`
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Title string
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Content string
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Created time.Time
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}
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func GetLink() beedb.Model {
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db, err := sql.Open("mymysql", "blog/astaxie/123456")
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if err != nil {
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panic(err)
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}
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orm := beedb.New(db)
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return orm
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}
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func GetAll() (blogs []Blog) {
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db := GetLink()
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db.FindAll(&blogs)
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return
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}
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func GetBlog(id int) (blog Blog) {
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db := GetLink()
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db.Where("id=?", id).Find(&blogs)
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return
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}
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func SaveBlog(blog Blog) (bg Blog) {
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db := GetLink()
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db.Save(&blog)
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return bg
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}
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func DelBlog(blog Blog) {
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db := GetLink()
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db.Delete(&blog)
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return
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}
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## view层
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layout.tpl
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<html>
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<head>
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<title>My Blog</title>
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<style>
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#menu {
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width: 200px;
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float: right;
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}
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</style>
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</head>
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<body>
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<ul id="menu">
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||||
<li><a href="/">Home</a></li>
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<li><a href="/new">New Post</a></li>
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</ul>
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||||
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{{.LayoutContent}}
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||||
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</body>
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</html>
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index.tpl
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<h1>Blog posts</h1>
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<ul>
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{{range .blogs}}
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<li>
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<a href="/view/{{.Id}}">{{.Title}}</a>
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from {{.Created}}
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<a href="/edit/{{.Id}}">Edit</a>
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<a href="/delete/{{.Id}}">Delete</a>
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</li>
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{{end}}
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</ul>
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||||
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view.tpl
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<h1>{{.Post.Title}}</h1>
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{{.Post.Created}}<br/>
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||||
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||||
{{.Post.Content}}
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||||
|
||||
new.tpl
|
||||
|
||||
<h1>New Blog Post</h1>
|
||||
<form action="" method="post">
|
||||
标题:<input type="text" name="title"><br>
|
||||
内容：<textarea name="content" colspan="3" rowspan="10"></textarea>
|
||||
<input type="submit">
|
||||
</form>
|
||||
|
||||
edit.tpl
|
||||
|
||||
<h1>Edit {{.Post.Title}}</h1>
|
||||
|
||||
<h1>New Blog Post</h1>
|
||||
<form action="" method="post">
|
||||
标题:<input type="text" name="title" value="{{.Post.Title}}"><br>
|
||||
内容：<textarea name="content" colspan="3" rowspan="10">{{.Post.Content}}</textarea>
|
||||
<input type="hidden" name="id" value="{{.Post.Id}}">
|
||||
<input type="submit">
|
||||
</form>
|
||||
|
||||
## links
|
||||
* [目录](<preface.md>)
|
||||
* 上一章: [controller设计](<13.4.md>)
|
||||
* 下一节: [实现博客的增删改](<13.6.md>)
|
||||
* 上一章: [数据库操作](<13.4.md>)
|
||||
* 下一节: [小结](<13.6.md>)
|
||||
Reference in New Issue
Block a user