Private/Classes/30-HttpRequest.ps1
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<# Object to facilitate sorting qualty-valued objects in a request header https://developer.mozilla.org/en-US/docs/Glossary/Quality_values #> class QualityValue { # Mime type [string]$Value # Number of wildcards in the mime type [int]$WildcardCount # Q-Value [double]$QValue <# Construct from mime type and Q-Value #> QualityValue([string]$type, [double]$qValue) { $this.Value = $type $this.QValue = $qValue $this.WildcardCount = $type.Split('*').Length - 1 } <# Construct from mime type only. Q-Value will be 1.0 #> QualityValue([string]$type) { $this.Value = $type $this.QValue = 1 $this.WildcardCount = $type.Split('*').Length - 1 } <# Compare function for sorting as per https://developer.mozilla.org/en-US/docs/Glossary/Quality_values #> [int]CompareTo([QualityValue]$other) { if ($null -eq $other) { return 1 } $cmp = $other.QValue.CompareTo($this.QValue) if ($cmp -ne 0) { # Q-Values are different - stop comparing here return $cmp } # If equal, compare wildcard count. More wildcards = lower precedence return $this.WildcardCount.CompareTo($other.WildcardCount) } [string]ToString() { return "$($this.Value);q=$($this.QValue)" } } <# Separate IComparer for QualityValue class Doesn't work when attempting to inherit QualityValue from IComparable<T> #> class QualityValueComparer : System.Collections.Generic.IComparer[QualityValue] { static [QualityValueComparer]$Comparer = [QualityValueComparer]::new() QualityValueComparer() { } [int]Compare([QualityValue]$x, [QualityValue]$y) { if ($null -eq $x -and $null -eq $y) { return 0 } if ($null -eq $x) { return 1 } if ($null -eq $y) { return -1 } return $x.CompareTo($y) } } <# Class to read and process an incoming HTTP request stream. #> class HttpRequest { # HTTP request stream hidden [System.IO.Stream]$HttpStream static [string[]]$SupportedRequestMethods = @('HEAD', 'GET', 'POST', 'PUT', 'DELETE', 'OPTIONS') # Number of bytes read so far from stream [int]$BytesRead = 0 # Request verb (GET etc.) [string]$RequestMethod # Request path (without any query string) [string]$Path # HTTP protocol version (1.0, 1.1 etc) [Version]$ProtocolVersion # Parsed query parameters (if any) [System.Collections.Specialized.NameValueCollection]$QueryParameters = $null # Parsed form parameters (if any) [System.Collections.Specialized.NameValueCollection]$FormParameters = $null # Parsed headers [hashtable]$Headers = @{} # List of Accept header mime types sorted by priority. [System.Collections.Generic.List[QualityValue]]$PrioritisedAcceptMimeTypes = [System.Collections.Generic.List[QualityValue]]::new() # List of Accept-Encoding types sorted by priority [System.Collections.Generic.List[QualityValue]]$PrioritisedAcceptEncodings = [System.Collections.Generic.List[QualityValue]]::new() <# Construct request object #> HttpRequest([System.IO.Stream]$httpStream) { $this.HttpStream = $httpStream } <# Read the incoming request stream and parse it #> [void]Read() { $sr = $null try { $sr = [System.IO.StreamReader]::new($this.HttpStream, [System.Text.Encoding]::UTF8, $true, 1024, $true) $requestLine = $sr.ReadLine() $this.BytesRead += $requestLine.Length + 2 # Parse the request line, e.g. GET /some/resource?param=value HTTP/1.0 if ($requestLine -match '^(?<verb>([A-Z]+))\s+(?<path>.*?)\s+HTTP/(?<protocol>\d\.\d)') { if ([HttpRequest]::SupportedRequestMethods -inotcontains $Matches.verb) { throw [HttpException]::new(501, "$($Matches.verb) not supported") } $this.RequestMethod = $Matches.verb $this.ProtocolVersion = [Version]::Parse($Matches.protocol) ($this.Path, $query) = $Matches.path.Split('?') if ($null -ne $query) { $this.QueryParameters = [System.Web.HttpUtility]::ParseQueryString($query) } } else { throw [HttpException]::new(400, "Invalid request") } # Read headers $this.Headers = @{} $line = $sr.ReadLine() $this.BytesRead += $line.Length + 2 while (-not ([string]::IsNullOrWhiteSpace($line))) { ($key, $value) = $line -split ':' $this.Headers.Add($key, $value.Trim()) $line = $sr.ReadLine() $this.BytesRead += $line.Length + 2 } # Validate POST content-type. # TODO: Support multipart encoding if ($this.RequestMethod -ieq 'POST' -and $this.Headers.ContainsKey('Content-Type')) { switch (($this.Headers['Content-Type'] -split ';')[0]) { 'application/x-www-form-urlencoded' { # Should read content by content length $this.FormParameters = [System.Web.HttpUtility]::ParseQueryString($sr.ReadLine()) } default { throw [HttpException]::new(400, "Content type $_ not supported") } } } } finally { if ($sr) { $sr.Dispose() } } $this.ParseAcceptHeaders() } <# Test for CORS request by presense of Access-Control-Request headers #> [bool]IsCorsRequest() { return $null -ne ($this.Headers.Keys | Where-Object { $_ -ilike 'Access-Control-Request*' } | Select-Object -First 1) } <# Reform the request header as a string, primarily for dfebugging. #> [string]RequestHeader() { $sb = [System.Text.StringBuilder]::new() $pathAndQuery = $this.Path + $( if ($null -eq $this.QueryParameters) { [string]::Empty } else { '?' + $this.QueryParameters.ToString() } ) $sb.AppendLine("$($this.RequestMethod) $($pathAndQuery) HTTP/$($this.ProtocolVersion.ToString())") | Out-Null $this.Headers.Keys | ForEach-Object { $sb.AppendLine("$($_): $($this.Headers[$_])") | Out-Null } return $sb.ToString() } <# Parse Accept and Accept-Encoding headers #> hidden [void]ParseAcceptHeaders() { if ($this.Headers.ContainsKey('Accept')) { $this.ParseQValueHeader('Accept', $this.PrioritisedAcceptMimeTypes) } else { # Assume the client will accept anything $this.PrioritisedAcceptMimeTypes.Add([QualityValue]::new('*/*')) } if ($this.Headers.ContainsKey('Accept-Encoding')) { $this.ParseQValueHeader('Accept-Encoding', $this.PrioritisedAcceptEncodings) } else { # If no Accept-Encoding, then assume client accepts 'identity' $this.PrioritisedAcceptEncodings.Add([QualityValue]::new('identity')) } } <# Parse Q-Value header into a sorted array https://developer.mozilla.org/en-US/docs/Glossary/Quality_values #> hidden [void]ParseQValueHeader([string]$headerName, [System.Collections.Generic.List[QualityValue]]$resultList) { $this.Headers[$headerName] -split ',' | ForEach-Object { $acc = $_.Trim() if ($acc -match '^(?<value>[\w\d\+\*/]+)(\s*\;\s*q=(?<qvalue>\d\.\d+))?') { if ($Matches.ContainsKey('qvalue')) { $resultList.Add([QualityValue]::new($matches.value, [double]::Parse($matches.qvalue))) } else { $resultList.Add([QualityValue]::new($matches.value)) } } } $resultList.Sort([QualityValueComparer]::Comparer) } } |