fix: allow lower-case header names as per RFC spec

Fixes: #310

Author: Steven Vancoillie

lib/utils/protocols/rtsp.ts

@@ -1,19 +1,55 @@
 /*
-Example data:
-RTSP/1.0 200 OK
-CSeq: 3
-Content-Type: application/sdp
-Content-Base: rtsp://192.168.0.3/axis-media/media.amp/
-Server: GStreamer RTSP server
-Date: Wed, 03 Jun 2015 14:23:42 GMT
-Content-Length: 623
+ * The RTSP response format is defined in RFC 7826,
+ * using ABNF notation specified in RFC 5234.
+ * Strings in ABNF rules ("...") are always case insensitive!
+ *
+ * Basic rules to help with the headers below:
+ * ====
+ * CR              =  %x0D ; US-ASCII CR, carriage return (13)
+ * LF              =  %x0A  ; US-ASCII LF, linefeed (10)
+ * SP              =  %x20  ; US-ASCII SP, space (32)
+ * HT              =  %x09  ; US-ASCII HT, horizontal-tab (9)
+ * CRLF            =  CR LF
+ * LWS             =  [CRLF] 1*( SP / HT ) ; Line-breaking whitespace
+ * SWS             =  [LWS] ; Separating whitespace
+ * HCOLON          =  *( SP / HT ) ":" SWS
+ *
+ * RTSP response rules (a `*` means zero or more):
+ * ====
+ * Status-Line  = RTSP-Version SP Status-Code SP Reason-Phrase CRLF
+ * Response     = Status-Line
+ *                *((general-header
+ *                /  response-header
+ *                /  message-body-header) CRLF)
+ *                CRLF
+ *                [ message-body-data ]
+ *
+ * Example response:
+ * ====
+ * RTSP/1.0 200 OK
+ * CSeq: 3
+ * Content-Type: application/sdp
+ * Content-Base: rtsp://192.168.0.3/axis-media/media.amp/
+ * Server: GStreamer RTSP server
+ * Date: Wed, 03 Jun 2015 14:23:42 GMT
+ * Content-Length: 623
+ *
+ * v=0
+ * ....
+ */
 
-v=0
-....
-*/
+/**
+ * Extract the value of a header.
+ *
+ * @param buffer The response bytes
+ * @param header The header to search for
+ */
 export const extractHeaderValue = (buffer: Buffer, header: string) => {
-  const anchor = `\n${header}: `
-  const start = buffer.indexOf(anchor)
+  const anchor = `\n${header.toLowerCase()}: `
+  const start = buffer
+    .toString()
+    .toLowerCase()
+    .indexOf(anchor)
   if (start >= 0) {
     const end = buffer.indexOf('\n', start + anchor.length)
     const headerValue = buffer
@@ -25,6 +61,10 @@ export const extractHeaderValue = (buffer: Buffer, header: string) => {
 }
 
 export const sequence = (buffer: Buffer) => {
+  /**
+   * CSeq           =  "CSeq" HCOLON cseq-nr
+   * cseq-nr        =  1*9DIGIT
+   */
   const val = extractHeaderValue(buffer, 'CSeq')
   if (val !== null) {
     return Number(val)
@@ -33,17 +73,29 @@ export const sequence = (buffer: Buffer) => {
 }
 
 export const sessionId = (buffer: Buffer) => {
+  /**
+   * Session          =  "Session" HCOLON session-id
+   *                     [ SEMI "timeout" EQUAL delta-seconds ]
+   * session-id        =  1*256( ALPHA / DIGIT / safe )
+   * delta-seconds     =  1*19DIGIT
+   */
   const val = extractHeaderValue(buffer, 'Session')
   return val ? val.split(';')[0] : null
 }
 
 export const sessionTimeout = (buffer: Buffer) => {
+  /**
+   * Session          =  "Session" HCOLON session-id
+   *                     [ SEMI "timeout" EQUAL delta-seconds ]
+   * session-id        =  1*256( ALPHA / DIGIT / safe )
+   * delta-seconds     =  1*19DIGIT
+   */
   const val = extractHeaderValue(buffer, 'Session')
   if (val === null) {
     return null
   }
   const timeoutToken = 'timeout='
-  const timeoutPosition = val.indexOf(timeoutToken)
+  const timeoutPosition = val.toLowerCase().indexOf(timeoutToken)
   if (timeoutPosition !== -1) {
     let timeoutVal = val.substring(timeoutPosition + timeoutToken.length)
     timeoutVal = timeoutVal.split(';')[0]
@@ -58,15 +110,43 @@ export const statusCode = (buffer: Buffer) => {
 }
 
 export const contentBase = (buffer: Buffer) => {
+  /**
+   * Content-Base       =  "Content-Base" HCOLON RTSP-URI
+   */
   return extractHeaderValue(buffer, 'Content-Base')
 }
 
 export const connectionEnded = (buffer: Buffer) => {
-  return extractHeaderValue(buffer, 'Connection') === 'close'
+  /**
+   * Connection         =  "Connection" HCOLON connection-token
+   *                       *(COMMA connection-token)
+   * connection-token   =  "close" / token
+   */
+  const connectionToken = extractHeaderValue(buffer, 'Connection')
+  return connectionToken !== null && connectionToken.toLowerCase() === 'close'
 }
 
 export const range = (buffer: Buffer) => {
-  // Possible range headers:
+  /**
+   * Range              =  "Range" HCOLON ranges-spec
+   * ranges-spec        =  npt-range / utc-range / smpte-range
+   *                       /  range-ext
+   * npt-range        =  "npt" [EQUAL npt-range-spec]
+   * npt-range-spec   =  ( npt-time "-" [ npt-time ] ) / ( "-" npt-time )
+   * npt-time         =  "now" / npt-sec / npt-hhmmss / npt-hhmmss-comp
+   * npt-sec          =  1*19DIGIT [ "." 1*9DIGIT ]
+   * npt-hhmmss       =  npt-hh ":" npt-mm ":" npt-ss [ "." 1*9DIGIT ]
+   * npt-hh           =  2*19DIGIT   ; any positive number
+   * npt-mm           =  2*2DIGIT  ; 0-59
+   * npt-ss           =  2*2DIGIT  ; 0-59
+   * npt-hhmmss-comp  =  npt-hh-comp ":" npt-mm-comp ":" npt-ss-comp
+   *                     [ "." 1*9DIGIT ] ; Compatibility format
+   * npt-hh-comp      =  1*19DIGIT   ; any positive number
+   * npt-mm-comp      =  1*2DIGIT  ; 0-59
+   * npt-ss-comp      =  1*2DIGIT  ; 0-59
+   */
+
+  // Example range headers:
   // Range: npt=now-
   // Range: npt=1154.598701-3610.259146
   const npt = extractHeaderValue(buffer, 'Range')
@@ -83,6 +163,11 @@ export const range = (buffer: Buffer) => {
  * @return {Number}      The body offset, or -1 if no header end found
  */
 export const bodyOffset = (chunk: Buffer) => {
+  /**
+   * Strictly speaking, it seems RTSP MUST have CRLF and doesn't allow CR or LF on its own.
+   * That means that the end of the header part should be a pair of CRLF, but we're being
+   * flexible here and also allow LF LF or CR CR instead of CRLF CRLF.
+   */
   const bodyOffsets = ['\n\n', '\r\r', '\r\n\r\n']
     .map(s => {
       const offset = chunk.indexOf(s)