cityuni-webserver/pageHandler/utils/process-preconditions.go

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package utils
import (
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"golang.captainalm.com/cityuni-webserver/utils/io"
"mime/multipart"
"net/http"
"net/textproto"
"strconv"
"strings"
"time"
)
func ProcessSupportedPreconditionsForNext(rw http.ResponseWriter, req *http.Request, modT time.Time, etag string, noBypassModify bool, noBypassMatch bool) bool {
theStrippedETag := GetETagValue(etag)
if noBypassMatch && theStrippedETag != "" && req.Header.Get("If-None-Match") != "" {
etagVals := GetETagValues(req.Header.Get("If-None-Match"))
conditionSuccess := false
for _, s := range etagVals {
if s == theStrippedETag {
conditionSuccess = true
break
}
}
if conditionSuccess {
WriteResponseHeaderCanWriteBody(req.Method, rw, http.StatusNotModified, "")
return false
}
}
if noBypassMatch && theStrippedETag != "" && req.Header.Get("If-Match") != "" {
etagVals := GetETagValues(req.Header.Get("If-Match"))
conditionFailed := true
for _, s := range etagVals {
if s == theStrippedETag {
conditionFailed = false
break
}
}
if conditionFailed {
SwitchToNonCachingHeaders(rw.Header())
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rw.Header().Del("Content-Type")
rw.Header().Del("Content-Length")
WriteResponseHeaderCanWriteBody(req.Method, rw, http.StatusPreconditionFailed, "")
return false
}
}
if noBypassModify && !modT.IsZero() && req.Header.Get("If-Modified-Since") != "" {
parse, err := time.Parse(http.TimeFormat, req.Header.Get("If-Modified-Since"))
if err == nil && modT.Before(parse) || strings.EqualFold(modT.Format(http.TimeFormat), req.Header.Get("If-Modified-Since")) {
WriteResponseHeaderCanWriteBody(req.Method, rw, http.StatusNotModified, "")
return false
}
}
if noBypassModify && !modT.IsZero() && req.Header.Get("If-Unmodified-Since") != "" {
parse, err := time.Parse(http.TimeFormat, req.Header.Get("If-Unmodified-Since"))
if err == nil && modT.After(parse) {
SwitchToNonCachingHeaders(rw.Header())
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rw.Header().Del("Content-Type")
rw.Header().Del("Content-Length")
WriteResponseHeaderCanWriteBody(req.Method, rw, http.StatusPreconditionFailed, "")
return false
}
}
return true
}
func ProcessRangePreconditions(maxLength int64, rw http.ResponseWriter, req *http.Request, modT time.Time, etag string, supported bool) []ContentRangeValue {
canDoRange := supported
theStrippedETag := GetETagValue(etag)
modTStr := modT.Format(http.TimeFormat)
if canDoRange {
rw.Header().Set("Accept-Ranges", "bytes")
}
if canDoRange && !modT.IsZero() && strings.HasSuffix(req.Header.Get("If-Range"), "GMT") {
newModT, err := time.Parse(http.TimeFormat, modTStr)
parse, err := time.Parse(http.TimeFormat, req.Header.Get("If-Range"))
if err == nil && !newModT.Equal(parse) {
canDoRange = false
}
} else if canDoRange && theStrippedETag != "" && req.Header.Get("If-Range") != "" {
if GetETagValue(req.Header.Get("If-Range")) != theStrippedETag {
canDoRange = false
}
}
if canDoRange && strings.HasPrefix(req.Header.Get("Range"), "bytes=") {
if theRanges := GetRanges(req.Header.Get("Range"), maxLength); len(theRanges) != 0 {
if len(theRanges) == 1 {
rw.Header().Set("Content-Length", strconv.FormatInt(theRanges[0].Length, 10))
rw.Header().Set("Content-Range", theRanges[0].ToField(maxLength))
} else {
theSize := GetMultipartLength(theRanges, rw.Header().Get("Content-Type"), maxLength)
rw.Header().Set("Content-Length", strconv.FormatInt(theSize, 10))
}
if WriteResponseHeaderCanWriteBody(req.Method, rw, http.StatusPartialContent, "") {
return theRanges
} else {
return nil
}
} else {
SwitchToNonCachingHeaders(rw.Header())
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rw.Header().Del("Content-Type")
rw.Header().Del("Content-Length")
rw.Header().Set("Content-Range", "bytes */"+strconv.FormatInt(maxLength, 10))
WriteResponseHeaderCanWriteBody(req.Method, rw, http.StatusRequestedRangeNotSatisfiable, "")
return nil
}
}
if WriteResponseHeaderCanWriteBody(req.Method, rw, http.StatusOK, "") {
return make([]ContentRangeValue, 0)
}
return nil
}
func GetMultipartLength(parts []ContentRangeValue, contentType string, maxLength int64) int64 {
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cWriter := &io.CountingWriter{Length: 0}
var returnLength int64 = 0
multWriter := multipart.NewWriter(cWriter)
for _, currentPart := range parts {
_, _ = multWriter.CreatePart(textproto.MIMEHeader{
"Content-Range": {currentPart.ToField(maxLength)},
"Content-Type": {contentType},
})
returnLength += currentPart.Length
}
_ = multWriter.Close()
returnLength += cWriter.Length
return returnLength
}
func WriteResponseHeaderCanWriteBody(method string, rw http.ResponseWriter, statusCode int, message string) bool {
hasBody := method != http.MethodHead && method != http.MethodOptions
if hasBody && message != "" {
rw.Header().Set("Content-Type", "text/plain; charset=utf-8")
rw.Header().Set("X-Content-Type-Options", "nosniff")
rw.Header().Set("Content-Length", strconv.Itoa(len(message)+2))
SetNeverCacheHeader(rw.Header())
}
rw.WriteHeader(statusCode)
if hasBody {
if message != "" {
_, _ = rw.Write([]byte(message + "\r\n"))
return false
}
return true
}
return false
}