Finish the page-handler.

Remove unneeded utils.
Migrate ETag calculation code.

pageHandler/page-handler.go

@@ -2,25 +2,37 @@ package pageHandler
 
 import (
 	"golang.captainalm.com/cityuni-webserver/conf"
+	"golang.captainalm.com/cityuni-webserver/pageHandler/utils"
+	"io"
+	"mime/multipart"
 	"net/http"
+	"net/textproto"
 	"net/url"
+	"strconv"
 	"strings"
 	"sync"
+	"time"
 )
 
 type PageHandler struct {
-	PageContentsCache        map[string][]byte
+	PageContentsCache        map[string]*CachedPage
 	PageProviders            map[string]PageProvider
 	pageContentsCacheRWMutex *sync.RWMutex
 	RangeSupported           bool
 	CacheSettings            conf.CacheSettingsYaml
 }
 
+type CachedPage struct {
+	Content     []byte
+	ContentType string
+	LastMod     time.Time
+}
+
 func NewPageHandler(config conf.ServeYaml) *PageHandler {
-	var thePCCMap map[string][]byte
+	var thePCCMap map[string]*CachedPage
 	var theMutex *sync.RWMutex
 	if config.CacheSettings.EnableContentsCaching {
-		thePCCMap = make(map[string][]byte)
+		thePCCMap = make(map[string]*CachedPage)
 		theMutex = &sync.RWMutex{}
 	}
 	return &PageHandler{
@@ -33,19 +45,127 @@ func NewPageHandler(config conf.ServeYaml) *PageHandler {
 }
 
 func (ph *PageHandler) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
-	//Provide processing for requests using providers
+	actualPagePath := strings.TrimRight(request.URL.Path, "/")
+	queryCollection, actualQueries := ph.GetCleanQuery(request)
+
+	var pageContent []byte
+	var pageContentType string
+	var lastMod time.Time
+
+	if ph.CacheSettings.EnableContentsCaching {
+		cached := ph.getPageFromCache(request.URL, actualQueries)
+		if cached != nil {
+			pageContent = cached.Content
+			pageContentType = cached.ContentType
+			lastMod = cached.LastMod
+		}
+	}
+
+	if pageContentType == "" {
+		if provider := ph.PageProviders[actualPagePath]; provider != nil {
+			pageContentType, pageContent = provider.GetContents(queryCollection)
+			lastMod = provider.GetLastModified()
+			if pageContentType != "" && ph.CacheSettings.EnableContentsCaching {
+				ph.setPageToCache(request.URL, actualQueries, &CachedPage{
+					Content:     pageContent,
+					ContentType: pageContentType,
+					LastMod:     lastMod,
+				})
+			}
+		}
+	}
+
+	allowedMethods := ph.getAllowedMethodsForPath(request.URL.Path)
+	allowed := false
+	if request.Method != http.MethodOptions {
+		for _, method := range allowedMethods {
+			if method == request.Method {
+				allowed = true
+				break
+			}
+		}
+	}
+
+	if allowed {
+
+		if pageContentType == "" {
+			utils.WriteResponseHeaderCanWriteBody(request.Method, writer, http.StatusNotFound, "Page Not Found")
+		} else {
+
+			switch request.Method {
+			case http.MethodGet, http.MethodHead:
+
+				writer.Header().Set("Content-Type", pageContentType)
+				writer.Header().Set("Content-Length", strconv.Itoa(len(pageContent)))
+				utils.SetLastModifiedHeader(writer.Header(), lastMod)
+				utils.SetCacheHeaderWithAge(writer.Header(), ph.CacheSettings.MaxAge, lastMod)
+				theETag := utils.GetValueForETagUsingByteArray(pageContent)
+				writer.Header().Set("ETag", theETag)
+
+				if utils.ProcessSupportedPreconditionsForNext(writer, request, lastMod, theETag, ph.CacheSettings.NotModifiedResponseUsingLastModified, ph.CacheSettings.NotModifiedResponseUsingETags) {
+
+					httpRangeParts := utils.ProcessRangePreconditions(int64(len(pageContent)), writer, request, lastMod, theETag, ph.RangeSupported)
+					if httpRangeParts != nil {
+						if len(httpRangeParts) <= 1 {
+							var theWriter io.Writer = writer
+							if len(httpRangeParts) == 1 {
+								theWriter = utils.NewPartialRangeWriter(theWriter, httpRangeParts[0])
+							}
+							_, _ = theWriter.Write(pageContent)
+						} else {
+							multWriter := multipart.NewWriter(writer)
+							writer.Header().Set("Content-Type", "multipart/byteranges; boundary="+multWriter.Boundary())
+							for _, currentPart := range httpRangeParts {
+								mimePart, err := multWriter.CreatePart(textproto.MIMEHeader{
+									"Content-Range": {currentPart.ToField(int64(len(pageContent)))},
+									"Content-Type":  {"text/plain; charset=utf-8"},
+								})
+								if err != nil {
+									break
+								}
+								_, err = mimePart.Write(pageContent[currentPart.Start : currentPart.Start+currentPart.Length])
+								if err != nil {
+									break
+								}
+							}
+							_ = multWriter.Close()
+						}
+					}
+				}
+			case http.MethodDelete:
+				ph.PurgeTemplateCache(actualPagePath)
+				ph.PurgeContentsCache(request.URL.Path, actualQueries)
+				utils.SetNeverCacheHeader(writer.Header())
+				utils.WriteResponseHeaderCanWriteBody(request.Method, writer, http.StatusOK, "")
+			}
+		}
+	} else {
+
+		theAllowHeaderContents := ""
+		for _, method := range allowedMethods {
+			theAllowHeaderContents += method + ", "
+		}
+
+		writer.Header().Set("Allow", strings.TrimSuffix(theAllowHeaderContents, ", "))
+		if request.Method == http.MethodOptions {
+			utils.WriteResponseHeaderCanWriteBody(request.Method, writer, http.StatusOK, "")
+		} else {
+			utils.WriteResponseHeaderCanWriteBody(request.Method, writer, http.StatusMethodNotAllowed, "")
+		}
+	}
 }
 
-func (ph *PageHandler) GetCleanQuery(request *http.Request) url.Values {
+func (ph *PageHandler) GetCleanQuery(request *http.Request) (url.Values, string) {
 	toClean := request.URL.Query()
 	provider := ph.PageProviders[request.URL.Path]
 	if provider == nil {
-		return make(url.Values)
+		return make(url.Values), ""
 	}
 	supportedKeys := provider.GetSupportedURLParameters()
 	toDelete := make([]string, len(toClean))
 	theSize := 0
-	for s := range toClean {
+	theQuery := ""
+	for s, v := range toClean {
 		noExist := true
 		for _, key := range supportedKeys {
 			if s == key {
@@ -56,19 +176,27 @@ func (ph *PageHandler) GetCleanQuery(request *http.Request) url.Values {
 		if noExist {
 			toDelete[theSize] = s
 			theSize++
+		} else {
+			for _, i := range v {
+				if i == "" {
+					theQuery += s + "&"
+				} else {
+					theQuery += s + "=" + i + "&"
+				}
+			}
 		}
 	}
 	for i := 0; i < theSize; i++ {
 		delete(toClean, toDelete[i])
 	}
-	return toClean
+	return toClean, strings.TrimRight(theQuery, "&")
 }
 
 func (ph *PageHandler) PurgeContentsCache(path string, query string) {
-	if ph.CacheSettings.EnableContentsCaching {
+	if ph.CacheSettings.EnableContentsCaching && ph.CacheSettings.EnableContentsCachePurge {
 		if path == "" {
 			ph.pageContentsCacheRWMutex.Lock()
-			ph.PageContentsCache = make(map[string][]byte)
+			ph.PageContentsCache = make(map[string]*CachedPage)
 			ph.pageContentsCacheRWMutex.Unlock()
 		} else {
 			if strings.HasSuffix(path, "/") {
@@ -114,3 +242,47 @@ func (ph *PageHandler) PurgeTemplateCache(path string) {
 		}
 	}
 }
+func (ph *PageHandler) getPageFromCache(urlIn *url.URL, cleanedQueries string) *CachedPage {
+	ph.pageContentsCacheRWMutex.RLock()
+	defer ph.pageContentsCacheRWMutex.RUnlock()
+	if strings.HasSuffix(urlIn.Path, "/") {
+		return ph.PageContentsCache[strings.TrimRight(urlIn.Path, "/")]
+	} else {
+		if cleanedQueries == "" {
+			return ph.PageContentsCache[urlIn.Path]
+		} else {
+			return ph.PageContentsCache[urlIn.Path+"?"+cleanedQueries]
+		}
+	}
+}
+
+func (ph *PageHandler) setPageToCache(urlIn *url.URL, cleanedQueries string, newPage *CachedPage) {
+	ph.pageContentsCacheRWMutex.Lock()
+	defer ph.pageContentsCacheRWMutex.Unlock()
+	if strings.HasSuffix(urlIn.Path, "/") {
+		ph.PageContentsCache[strings.TrimRight(urlIn.Path, "/")] = newPage
+	} else {
+		if cleanedQueries == "" {
+			ph.PageContentsCache[urlIn.Path] = newPage
+		} else {
+			ph.PageContentsCache[urlIn.Path+"?"+cleanedQueries] = newPage
+		}
+	}
+}
+
+func (ph *PageHandler) getAllowedMethodsForPath(pathIn string) []string {
+	if strings.HasSuffix(pathIn, "/") {
+		if (ph.CacheSettings.EnableTemplateCaching && ph.CacheSettings.EnableTemplateCachePurge) ||
+			(ph.CacheSettings.EnableContentsCaching && ph.CacheSettings.EnableContentsCachePurge) {
+			return []string{http.MethodHead, http.MethodGet, http.MethodOptions, http.MethodDelete}
+		} else {
+			return []string{http.MethodHead, http.MethodGet, http.MethodOptions}
+		}
+	} else {
+		if ph.CacheSettings.EnableContentsCaching && ph.CacheSettings.EnableContentsCachePurge {
+			return []string{http.MethodHead, http.MethodGet, http.MethodOptions, http.MethodDelete}
+		} else {
+			return []string{http.MethodHead, http.MethodGet, http.MethodOptions}
+		}
+	}
+}

pageHandler/page-provider.go

@@ -1,10 +1,14 @@
 package pageHandler
 
-import "net/url"
+import (
+	"net/url"
+	"time"
+)
 
 type PageProvider interface {
 	GetPath() string
 	GetSupportedURLParameters() []string
+	GetLastModified() time.Time
 	GetContents(urlParameters url.Values) (contentType string, contents []byte)
 	PurgeTemplate()
 }

pageHandler/utils/buffered-writer.go

@@ -1,23 +0,0 @@
-package utils
-
-import (
-	"crypto"
-	"encoding/hex"
-)
-
-type BufferedWriter struct {
-	Data []byte
-}
-
-func (c *BufferedWriter) Write(p []byte) (n int, err error) {
-	c.Data = append(c.Data, p...)
-	return len(p), nil
-}
-
-func (c *BufferedWriter) GetHashString() string {
-	theHash := crypto.SHA1.New()
-	_, _ = theHash.Write(c.Data)
-	theSum := theHash.Sum(nil)
-	theHash.Reset()
-	return hex.EncodeToString(theSum)
-}

pageHandler/utils/etag.go

@@ -1,11 +1,17 @@
 package utils
 
 import (
+	"crypto"
+	"encoding/hex"
 	"strings"
 )
 
-func GetValueForETagUsingBufferedWriter(bWriter *BufferedWriter) string {
-	return "\"" + bWriter.GetHashString() + "\""
+func GetValueForETagUsingByteArray(b []byte) string {
+	theHash := crypto.SHA1.New()
+	_, _ = theHash.Write(b)
+	theSum := theHash.Sum(nil)
+	theHash.Reset()
+	return "\"" + hex.EncodeToString(theSum) + "\""
 }
 
 func GetETagValues(stringIn string) []string {