pages - types.go

     1  package pages
     2  
     3  import (
     4  	"html/template"
     5  	"net/http"
     6  	"os"
     7  	"sync"
     8  	"time"
     9  )
    10  
    11  const (
    12  	Static         = "-static-"
    13  	StaticTemplate = "{{define \"title\"}}{{.Title}}{{end}}{{define \"style\"}}{{.Style}}{{end}}{{define \"body\"}}\n{{.Body}}{{end}}"
    14  )
    15  
    16  type staticData struct {
    17  	Title, Style string
    18  	Body         template.HTML
    19  }
    20  
    21  type Bytes struct {
    22  	pages      *Pages
    23  	staticData staticData
    24  }
    25  
    26  func (p *Pages) Bytes(title, style string, body template.HTML) *Bytes {
    27  	if _, ok := p.templates[Static]; !ok {
    28  		p.StaticString(StaticTemplate)
    29  	}
    30  	return &Bytes{
    31  		pages: p,
    32  		staticData: staticData{
    33  			Title: title,
    34  			Style: style,
    35  			Body:  body,
    36  		},
    37  	}
    38  }
    39  
    40  func (b *Bytes) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    41  	b.pages.Write(w, r, Static, &b.staticData)
    42  }
    43  
    44  type File struct {
    45  	pages    *Pages
    46  	Filename string
    47  
    48  	mu           sync.RWMutex
    49  	staticData   *staticData
    50  	LastModified time.Time
    51  }
    52  
    53  func (p *Pages) File(title, style, filename string) *File {
    54  	if _, ok := p.templates[Static]; !ok {
    55  		p.StaticString(StaticTemplate)
    56  	}
    57  	return &File{
    58  		pages:    p,
    59  		Filename: filename,
    60  		staticData: &staticData{
    61  			Title: title,
    62  			Style: style,
    63  		},
    64  	}
    65  }
    66  
    67  func (f *File) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    68  	stats, err := os.Stat(f.Filename)
    69  	if err != nil {
    70  		w.WriteHeader(http.StatusInternalServerError)
    71  		return
    72  	}
    73  	if modtime := stats.ModTime(); modtime.After(f.LastModified) {
    74  		f.mu.Lock()
    75  		stats, err = os.Stat(f.Filename)
    76  		if err != nil {
    77  			f.mu.Unlock()
    78  			w.WriteHeader(http.StatusInternalServerError)
    79  			return
    80  		}
    81  
    82  		if modtime = stats.ModTime(); modtime.After(f.LastModified) { // in case another goroutine has changed it already
    83  			data, err := os.ReadFile(f.Filename)
    84  			if err != nil {
    85  				f.mu.Unlock()
    86  				w.WriteHeader(http.StatusInternalServerError)
    87  				return
    88  			} else {
    89  				f.staticData = &staticData{
    90  					Title: f.staticData.Title,
    91  					Style: f.staticData.Style,
    92  					Body:  template.HTML(data),
    93  				}
    94  				f.LastModified = modtime
    95  			}
    96  		}
    97  		f.mu.Unlock()
    98  	}
    99  	f.mu.RLock()
   100  	staticData := f.staticData
   101  	f.mu.RUnlock()
   102  	f.pages.Write(w, r, Static, staticData)
   103  }
   104