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1. The HTTP parser module PRINTED MANUAL 1999 2008 AGG Software HTTP parser module 1999 2008 AGG Software All rights reserved No parts of this work may be reproduced in any form or by any means graphic electronic or mechanical including photocopying recording taping or information storage and retrieval systems without the written permission of the publisher Products that are referred to in this document may be either trademarks and or registered trademarks of the respective owners The publisher and the author make no claim to these trademarks While every precaution has been taken in the preparation of this document the publisher and the author assume no responsibility for errors or omissions or for damages resulting from the use of information contained in this document or from the use of programs and source code that may accompany it In no event shall the publisher and the author be liable for any loss of profit or any other commercial damage caused or alleged to have been caused directly or indirectly by this document Printed 25 09 2008 Publisher AGG Software Production 1999 2008 AGG Software http www aggsoft com Contents l Table of Contents Part 1 Introduction 1 Part 2 System requirements 1 Part 3 Installing HTTP parser module 2 Part 4 Glossary 5 Part 5 User Manual 6 t Parsing dala oanien E Rhe EAA E aa 6 FR cl e a eee A ER A LEER E Ay NE 10 3 Syntax of Regula2. 1999 2008 AGG Software Installing HTTP parser module cE Port options Data export Log file Select data export modules Other Module name Version C OPC server buildin dll 3 2 0 14 DDE Server ddesrv dll 3 2 0 1 C Local database localdb dll 3 2 0 3 C ODBC database odbcexport dil 3 2 0 3 Query Parse Filter C Direct Excel connection olexcel dll 3 2 0 8 E Send keystrokes wndem dll 3 2 0 2 ES C Excel export excelexport dil 3 0 0 19 Data export FS Download plugin now Help Setup Redirect data to another configuration Events handling Configuration Fig 2 Examples of installed modules 1999 2008 AGG Software 5 HTTP parser module Port options Events handling Log file Select events handling modules J Module name Version C Events notification events dll 3 2 0 2 C Internet sharing ishare dll 3 2 0 2 i Query Parse Filter Data export Events handling Download plugin now Fig 3 Examples of installed modules 4 Glossary Plug in module Main program the program shell that uses this module For example Advanced Serial Data Logger Parser the module that processes the data flow singling out data packets from it and variables from data packets These variables are used in data export modules after that Core see Main program 1999 2008 AGG Software
3. 404 or from a file or a folder 2 System requirements The following requirements must be met for HTTP parser module to be installed Operating system e Windows 95 Windows 95 OSR2 Windows 98 Windows Me Windows NT4 Windows 2000 Windows XP all editions both x86 and x64 Windows 2003 Server both x86 and x64 Windows Vista both x86 and x64 Free disk space Not less than 5 MB of free disk space is recommended Special access requirements You should log on as a user with Administrator rights in order to install this module The main application core must be installed for example Advanced Serial Data Logger Notes for Microsoft Vista Since our software saves data to the registry and installs to the Program Files folder the following requirements must be met 1 You need Administrator rights to run and install our software 1999 2008 AGG Software System requirements 2 2 The shortcut icon of our software will be located on the desktop 3 Windows Vista will ask for your confirmation to continue the installation NOTE You can configure the user account only once in order not to see the above dialog box any more Search Google for the solution of this problem Installing HTTP parser module Close the main application for example Advanced Serial Data Logger if it is running Copy the program to your hard drive Run the module installation file with a double click on the file
4. Example Please take a look at the example below it is a typical HTTP request GET js some js HTTP 1 1 Host 127 0 0 1 10000 User Agent Mozilla 5 0 Windows U Windows NT 5 1 rv 1 8 1 17 Gecko 20080829 Firefox 2 0 0 17 Accept Accept Language q 0 8 en us q 0 5 en q 0 3 Accept Charset windows 1250 utf 8 q 0 7 q 0 7 Keep Alive 300 Connection keep alive Referer http 127 0 0 1 10000 incl metal txt The data above consists of several strings with different length all values in the string are delimited by In our case they are e Host the string 127 0 0 1 10000 e User Agent user agent e and so on The parameter window is located on the Data parsing page fig 2 You may add several variables and specify their parameters and a data type string date time etc Each variable in the list may have a different parsing type Data types supported by the module are listed below 1999 2008 AGG Software User Manual 8 if Http parser 3 2 1 build 6 Data parsing Parser items 8 User Agent Item name USER AGENT Parser s type Http header field Data type String hp Default value Data parsing m eed Data format imr Fig 2 Parsing options 1 Http header field The parser will extract a field from a header with name which you ll define in the Item name field Additionally you can specify the data type and default value for this
5. User Manual 6 User Manual Parsing data The request message consists of the following e Request line such as GET images logo gif HTTP 1 1 which requests the file logo gif from the images directory e Headers such as Accept Language en e An empty line e An optional message body The request line and headers must all end with CR LF that is a carriage return followed by a line feed The empty line must consist of only lt CR gt lt LF gt and no other whitespace In the HTTP 1 1 protocol all headers except Host are optional The parser verifies an HTTP message and extracts all fields from a header or message body The parser doesn t work with body of multipart mixed POST requests i Http parser 3 2 1 build 6 General C Add date time stamp to each data packet parsed General C Add a serial port number to each data packet parsed Maximum request size D unlimited 65535 Request timeout ms 30000 Export whole HTTP header C Parse and export invalid or partial HTTP requests Data parsing E Please set following options in TCP IP port settings Oat Send client information to a parser Before each data packet Include remote port number On Adjust number of characters Off Prefix Postfix HODHOA Fig 1 General options Data format e Add a time stamp to each data packet the parser will add the new data stamp variable to each data packet that will be parsed into
6. field 2 Query string field Same as above but works with an HTTP request body query string 3 Fixed position Allows you to extract data from a fixed position in your HTTP requests It is useful if you want to extract the method of a HTTP request POST or GET 4 Delimited Allows you to extract values which are delimited by any character or text In our case you can extract header field using the delimiter 5 None If you select this type the parser will not extract a value from the data packet but will just create a variable with the NULL value 6 Default If you select this type the parser will not single out a value from the data packet but will just create a variable with the value you specify in the Default value field 1999 2008 AGG Software HTTP parser module 7 Regular expression a widely used data parsing method that uses templates with certain syntax to search for data The general rules of specifying regular expressions are described in next chapter In this mode you must specify regular expression text with one subexpression Result of this subexpression will be used as parsing result Data formatting You can use the following tab to specify the data format for some data types fig 3 i Http parser 3 2 1 build 6 Data format Text items format General C Trim spaces from left C Trim spaces from right Date and time format Date items DD MM YYYY Time
7. items HH NN SS DateTime items DD MM YYYY HH NN SS Note Any non alpha numerical characters must be quoted Data parsing Example or characters you must enter as 7 or t C Use current date for missing parts of date T C Use current time for missing parts of time Fr Data format Locale language ID 49 m Default value 0 403 English language Fig 3 Data format Text data format this group of options allows you to remove leading and or trailing spaces in variables of the String type Date and time format it often happens that the date or time format the external device sends does not coincide with the format in which this data is stored in the database To convert the date into the necessary format you should specify the format the date and time is received in The same format is used to specify the date and time as the one that is used in the name of the log file in the main program for example Advanced Serial Data Logger So read about it in the help file of the main program Note the and or characters are enclosed in quotation marks in the template see fig 4 If some part is missing in the received date and time for example year you can take the missing part from the current date and time 1999 2008 AGG Software User Manual 10 Use the current date for missing parts Use the current time for missing parts Sometimes devices send dates with month
8. names for example Jan 10 2005 and this name can be in a language in this example it is in English different from the language of your operating system The language ID the date is sent in is specified in the Date language ID field in this case Data types String String value Character array with length from 1 to 65535 characters Memo String value Character array with length from 1 to 2 32 characters Bytes Binary value Blob Binary Large Object field bytes set Boolean Logical value True False 0 or 1 Float Real number value range 2 9 x 10 39 1 7 x 10 38 Smallint Signed small integer value range 32768 32767 Word Word unsigned small integer value range 0 65535 Integer Signed integer value 2147483648 2147483647 Date Date Time Time DateTime Date and time 5 2 Filter The filter is used to ignore some data packets that you do not want to export with the help of other modules Filter Filter rules data packets level Situation Type Expression Action Text R Parse Fig 1 Filtering rules You should define one or several filtering rules If some condition is true the program does what 1999 2008 AGG Software 11 HTTP parser module 5 3 is specified in the Action field with the matching packet Action types e Ignore the current data packet will be ignored and will not be exported e Parse t
9. of characters in the target string so the pattern bluh would match bluh in the target string Quite simple eh You can cause characters that normally function as metacharacters or escape sequences to be interpreted literally by escaping them by preceding them with a backslash for instance metacharacter match beginning of string but match character V match and so on 1999 2008 AGG Software User Manual 12 Examples foobar matchs string foobar V FooBarPtr matchs FooBarPtr Escape sequences Characters may be specified using a escape sequences syntax much like that used in C and Perl n matches a newline t a tab etc More generally nn where nn is a string of hexadecimal digits matches the character whose ASCII value is nn If You need wide Unicode character code You can use x nnnn where nnnn one or more hexadecimal digits xnn char with hex code nn x nnnn char with hex code nnnn one byte for plain text and two bytes for Unicode t tab HT TAB same as x09 n newline NL same as x0a r car return CH same as xod f form feed FF same as x0c a alarm bell BEL same as 07 e escape ESC same as x1b Examples foo x20bar matchs foo bar note space in the middle tfoobar matchs foobar predefined by tab Character classes You can specify a character class by enclosing a list of characters in which will match any one character fr
10. only string in line foob r matchs strings like foobar foobbr foobir and so on The metacharacter by default is only guaranteed to match at the beginning of the input string text the metacharacter only at the end Embedded line separators will not be matched by HAM Or You may however wish to treat a string as a multi line buffer such that the will match after any line separator within the string and will match before any line separator The metacharacter by default matches any character Note that an empty line pattern doesnot match the empty string within the sequence xOD xOA but matchs the empty string within the sequence xOA x0D Metacharacters predefined classes w an alphanumeric character including _ W a nonalphanumeric d a numeric character D a non numeric s any space same as t n r f S a non space You may use W d and s within custom character classes Examples foob dr matchs strings like foob1r foob6r and so on but not foobar foobbr and so on foob w s r matchs strings like foobar foob r f oobbr and so on but not foob1r foob r and so on Metacharacters iterators Any item of a regular expression may be followed by another type of metacharacters iterators Using this metacharacters You can specify number of occurences of previous character metacharacter or subexpression 1999 2008 AGG Software User Man
11. variables e Add a port number to each data packet the parser will add the new port number variable to each data packet that will be parsed into variables It will allow you to identify data during export if you collect data from several devices at the same time 1999 2008 AGG Software HTTP parser module e Maximum request size you can specify the size of the request This options allows you to protect the server from bad large request messages If this values is greater than zero then the parser will parse first N bytes only Request timeout if the parser didn t receive a valid HTTP request from the client within this interval then the parser may ignore this request and don t export data Export whole HTTP header if this option is on then the parser will parse and export all header items Otherwise the parser will export which you ll define on the Data parsing page If you ll define the variable on the Data parsing page then you can additionally convert header items to any data type Parse and export invalid or partial HTTP requests if this option is on then the parser will parse and export HTTP requests which don t match the HTTP specification or received partially Data parsing variants You can find several real life examples on our site where different data parsing methods are used It can help you understand how the parser works http www aggsoft com serial data logger tutorials htm
12. a Yes or No answer The analysis of the additional information will help you locate the error Unable to verify your SQL script 26s the message appears when an attempt to analyze your SQL query fails Check if the syntax of your SQL query is correct Tested successfully the message appears if your database connection is successfully tested It requires no additional actions Database isn t used the message appears if the module is temporarily disabled the Temporarily disabled check box is selected or the database name field is empty Check the connection parameters Database isn t selected the message appears if the database type is not selected Check the connection parameters Database s s contains the database name The message appears if the database connection is successful Usually you see it when you call the module for the first time It requires no additional actions Invalid data block length columns d length d an internal application error It means that the data sent by the parser is in an invalid format Perhaps you are using the module incompatible with the version of the Advanced Serial Data Logger kernel Update the versions of both the kernel and the module The time of connection is not due yet d d the message appears during an attempt to connect to the database after the connection to it has been lost and the Reconnect after option is enabled No additional actions are requ
13. and send it with the 200 OK status code The module will ignore a file name which is specified in the HTTP request If the file doesn t exist then the module will return the 404 message From root folder the module extracts a file name from the HTTP request and search this file in the specified folder If the file exists then module send it with the 200 OK status code Otherwise the module will return the 404 message We recommend to use the Autodetect content type for this response type 1999 2008 AGG Software Troubles 18 Troubles Possible problems No data for publication exporting no data is passed for exporting Solution configure the parser make sure that one or more variables are declared in the parser Error on binding variable with name s s the error usually occurs if data does not correspond to the specified format For example the date and time format does not correspond to the data Unable to disconnect from the database s and Unable to connect to a database s it is impossible to connect disconnect to form the database You should check the parameters of the database connection The analysis of the additional information will help you locate the error Database access error s Stop operations with the database the message appears if an error occurs during an attempt to execute an SQL query if the second variant of reacting to errors is selected The message implies
14. ch g Non standard modifier Switching it Off You ll switch all following operators into non greedy mode by default this modifier is On So if modifier g is Off then works as as and so on x Extend your pattern s legibility by permitting whitespace and comments see explanation below The modifier x itself needs a little more explanation It tells the parser to ignore whitespace that is neither backslashed nor within a character class You can use this to break up your regular expression into slightly more readable parts The character is also treated as a metacharacter introducing a comment for example 1999 2008 AGG Software 5 4 User Manual 16 abc comment 1 You can use spaces to format r e parser ignores it efg comment 2 This also means that if you want real whitespace or characters in the pattern outside a character class where they are unaffected by x that you ll either have to escape them or encode them using octal or hex escapes Taken together these features go a long way towards making regular expressions text more readable How to change modifiers imsxr imsxr You may use it into r e for modifying modifiers by the fly If this construction inlined into subexpression then it effects only into this subexpression Examples i New York matchs New york and New York i New i York matchs New York but not New york i New York
15. he current data packet will be parsed and exported There are several condition types that are specified in the Status field Rule status types e Disabled this rule is disabled and not used for filtering purposes e Contains this rules checks whether the string expression from the Expression field is present in the data packet e Does not contain this rules checks whether the string expression from the Expression field is absent in the data packet Expressions types Expressions in the Expression field can be of 2 types e Text the module will search the data packet for a string specified in the Expression field The search is case sensitive e Regular expression the module will use the regular expression specified in the Expression field in its search The search is case sensitive Syntax of Regular Expressions Introduction Regular Expressions are a widely used method of specifying patterns of text to search for Special metacharacters allow You to specify for instance that a particular string You are looking for occurs at the beginning or end of a line or contains n recurrences of a certain character Regular expressions look ugly for novices but really they are very simple handy and powerful tool Let s start our learning trip Simple matches Any single character matches itself unless it is a metacharacter with a special meaning described below A series of characters matches that series
16. ired Invalid procedure call Bad arguments an attempt to call the module using invalid parameters Perhaps you are using the module incompatible with the version of the Advanced Serial Data Logger kernel Update the versions of both the kernel and the module Writing to the database is complete the message appears if your queue of SQL queries is successfully executed It requires no additional actions 1999 2008 AGG Software 19 HTTP parser module Writing to the database is complete with errors the message appears if the executing your queue of SQL queries was interrupted by an error It requires no additional actions Your SQL is empty Please specify some SQL text first the message appears if you do not enter the text for your SQL query Check if the options on the SQL queue tab are configured correctly Invalid temporary path the path to the temporary file specified by you does not exist Enter a new path in the Temporary folder field on the Errors handling tab 96s d will be replaced by additional information 1999 2008 AGG Software
17. matchs New york and new york i New York matchs New York but not new york text A comment the text is ignored Note that parser closes the comment as soon as it sees a so there is no way to put a literal in the comment Response Upon receiving the request the module may send back a status line such as HTTP 1 1 200 OK and a message of its own the body of which is perhaps the requested file an error message or some other information Content type specifies the Internet media type of the data conveyed by the http message 1999 2008 AGG Software 17 HTTP parser module i Http parser 3 2 1 build 6 5 Response Filter Response type content type From root folder Autodetect Folder with files E wa Data parsing gt PN Data format d Response E Cancel Fig 5 Response options The module allows supports following response types Disabled the module will not send responses at all Please note that most HTTP clients will wait any response 403 the module will always send a response message with the 403 Forbidden status code 404 the module will always send a response message with the 404 Not Found status code Text you may define any plain text or HTML in the corresponding field The module will send it with the 200 OK status code From file the module may read response from a text or binary file
18. name in Windows Explorer Follow the instructions of the installation software Usually it is enough just to click the Next button several times Start the main application The name of the module will appear on the Modules tab of the Settings window if it is successfully installed ROD o If the module is compatible with the program its name and version will be displayed in the module list You can see examples of installed modules on fig 1 2 Some types of modules require additional configuration To do it just select a module from the list and click the Setup button next to the list The configuration of the module is described below You can see some types of modules on the Log file tab To configure such a module you should select it from the File type list and click the Advanced button 1999 2008 AGG Software HTTP parser module cE Port options Query Parse Filter Log file Data query module Biber J ASCII data query and parser default dll iv Parser module ASCII data query and parser default dll m Parsing and exporting for data sent Parsing and exporting for data received Query Parse Filte i Select data filter modules Module name Version AS C Expressions expressions dll 3 2 0 2 C Aggregation aggregator dll 3 2 0 1 Data export C Deadband deadband dll 3 2 0 1 Events handling Fig 1 Examples of installed modules
19. om the list If the first character after the is the class matches any character not in the list Examples foob aeiou r finds strings foobar toober etc but not foobbr foobcr etc foob aeiou r find strings foobbr foobcr etc but not foobar Toober etc Within a list the character is used to specify a range so that a z represents all characters between a and Z inclusive If You want itself to be a member of a class put it at the start or end of the list or escape it with a backslash If You want you may place it at the start of list or escape it with a backslash Examples az matchs a z and az matchs a z and a V z matchs a z and a z matchs all twenty six small characters from a to z n xOD matchs any of 10 11 12 13 d t matchs any digit or t a matchs any char from a 1999 2008 AGG Software 13 HTTP parser module Metacharacters Metacharacters are special characters which are the essence of Regular Expressions There are different types of metacharacters described below Metacharacters line separators start of line end of line A start of text Z end of text any character in line Examples foobar matchs string foobar only if it s at the beginning of line foobar matchs string foobar only if it s at the end of line foobar matchs string foobar only if it s the
20. oo 1999 2008 AGG Software 15 HTTP parser module Metacharacters subexpressions The bracketing construct may also be used for define r e subexpressions Subexpressions are numbered based on the left to right order of their opening parenthesis First subexpression has number 1 Examples foobar 8 10 matchs strings which contain 8 9 or 10 instances of the foobar foob 0 9 a r matchs foobOr foobir foobar foobaar foobaar etc Metacharacters backreferences Metacharacters 1 through 9 are interpreted as backreferences lt n gt matches previously matched subexpression lt n gt Examples M matchs aaaa and cc 1 also match abab and 123123 ld 1 matchs 13 in double quotes or 4 in single quotes or 77 without quotes etc Modifiers Modifiers are for changing behaviour of parser There are many ways to set up modifiers Any of these modifiers may be embedded within the regular expression itself using the construct i Do case insensitive pattern matching using installed in you system locale settings m Treat string as multiple lines That is change and from matching at only the very start or end of the string to the start or end of any line anywhere within the string s Treat string as single line That is change to match any character whatsoever even a line separators which it normally would not mat
21. possible non greedy takes as few as possible For example b and b applied to string abbbbc return bbbb b returns b b returns empty string b 2 3 returns bb b 2 3 returns bbb Metacharacters alternatives You can specify a series of alternatives for a pattern using to separate them so that fee fie foe will match any of fee fie or foe in the target string as would f e iJo e The first alternative includes everything from the last pattern delimiter or the beginning of the pattern up to the first and the last alternative contains everything from the last to the next pattern delimiter For this reason it s common practice to include alternatives in parentheses to minimize confusion about where they start and end Alternatives are tried from left to right so the first alternative found for which the entire expression matches is the one that is chosen This means that alternatives are not necessarily greedy For example when matching foo foot against barefoot only the foo part will match as that is the first alternative tried and it successfully matches the target string This might not seem important but it is important when you are capturing matched text using parentheses Also remember that is interpreted as a literal within square brackets so if You write fee fie foe You re really only matching feio Examples foo bar foo matchs strings foobar or foof
22. r Expressions ccsscccesseesseeeeeeeeeseeeeeneeeeesecaesnseeeesesaeseseeaeeseeesasneeeenennes 11 AP RESPONSE n eei nel t els estes e ien iei se eeeteE ces 16 Part 6 Troubles 18 1 Possible problems 11eeeeeeeeeeeeeeeeee eanna annainn a nanan anaiak nnnm r ans nn nnn ns sn annt 18 1999 2008 AGG Software 1 HTTP parser module 1 Introduction This parser module mostly works together with Advanced TCP IP Data Logger and implements very basic HTTP server features Hypertext Transfer Protocol HTTP is a communications protocol for the transfer of information on the Internet HTTP is a request response standard between a client and a server A client is your device the server is our application The client making an HTTP request and send any data Our software parse requests and can export it with many data export modules The parser allows you to parse and export variables from a HTTP header and a HTTP request body string and sends answers if this is necessary This isn t required to install other HTTP servers and create any scripts for web servers to collect and export data from your devices Key features Parsing of a HTTP header Parsing of a query string Detects a request method POST or GET and a protocol automatically Allows extract and convert parser items from the string data type to other data types The parser can filter requests Allows you to send responses with code 403
23. ual 14 n zero or more greedy similar to 0 one or more greedy similar to 1 Zero or one greedy similar to 0 1 n exactly n times greedy n at least n times greedy n m atleast n but not more than m times greedy 9 zero or more non greedy similar to 0 one or more non greedy similar to 1 zero or one non greedy similar to 0 1 n exactly n times non greedy n atleast n times non greedy n m at least n but not more than m times non greedy So digits in curly brackets of the form n m specify the minimum number of times to match the item n and the maximum m The form n is equivalent to n n and matches exactly n times The form n matches n or more times There is no limit to the size of n or m but large numbers will chew up more memory and slow down r e execution If a curly bracket occurs in any other context it is treated as a regular character Examples foob r matchs strings like foobar foobalkjdflkj9r and foobr foob r matchs strings like foobar foobalkjdflkj9r but not foobr foob r matchs strings like foobar foobbr and foobr but not foobalkj9r fooba 2 r matchs the string foobaar fooba 2 r X matchs strings like toobaar foobaaar foobaaaar etc fooba 2 3 r matchs strings like foobaar or foobaaar but not foobaaaar A little explanation about greediness Greedy takes as many as
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