Stata web services: Toward Stata-based healthcare informatics applications integrated

Transcription

1 Stata web services: Toward Stata-based healthcare informatics applications integrated in a service-oriented architecture (SOA) Alexander Zlotnik Technical University of Madrid, ETSIT, DIE Ramon y Cajal University Hospital Modesto Escobar Universidad de Salamanca Ascensión Gallardo-Antolín UC3M, Department of Signals and Systems, Madrid Juan Manuel Montero Martínez Technical University of Madrid, ETSIT, DIE Stata is a registered trademark of StataCorp LP, College Station, TX, USA.

2 Why?

3 User-contributed programs ssc install <program> findit <program> (runs both searchand and net search) net from manually copy program files to C:\ado\plus\<subdir>\ \

4 Sometimes this is not enough

5 Sometimes your program requires complex interactions with external software packages (ex: WinBUGS, MATLAB, Maxima, AnyLogic) uses proprietary data sources (ex: real-time currency exchange rates) uses proprietary source code

6 Sometimes your users does nothave the version of Statayour program requires (ex: it may require v14 and they may only have v12) does nothave Stataat all (Statais not very common in some fields) does nothave a PC, but may have a smartphonewith a web browser (ex: developing countries)

7 What if? Private data sources Your program Stata / Mata External programs Your server

8 What if? Private data sources Your program Web interface Stata / Mata Access from any device External programs Your server

9 What if? Private data sources Your program Web interface Stata / Mata Access from any device External programs Security: client isolation

10 Sometimes your program requires complex interactions with external software packages (ex: WinBUGS, MATLAB, Maxima, AnyLogic) uses proprietary data sources (ex: real-time currency exchange rates) uses proprietary source code

11 What if? Private data sources Your program Stata / Mata Web service XML External programs

12 What if? Web service XML Web applications Desktop applications Mobile applications native ios apps native Android apps WSDL SOAP

13 Service-oriented architecture Web service XML Enterprise Service Bus Other web services WSDL SOAP

14 How?

15 How? Your program Option 1: Translate Stata/ Mata program into a general-purpose programming language used in web applications. Ex: Java, C / C++, C#, ASP.net+ VB.net, Python, Ruby, etc

16 How? Your program Option 1: Translate Stata/ Mata program into a general-purpose programming language used in web applications. Ex: Java, C / C++, C#, ASP.net+ VB.net, Python, Ruby, etc - Few numerical libraries -May nothave the same functions -Functions may notbe implemented in the same way -- subtle errors -- numerical precision issues -- performance issues

17 How? Your program Option 2: Translate Stata/ Mata program into R & RShinyorSAS Stored Process Web Application

18 How? Your program Option 2: Translate Stata/ Mata program into R & RShinyorSAS Stored Process Web Application -Still requires a laborious translation in most cases -Again, functions may notbe implemented in the same way -RShinyis is a nice alternative but the free version only supports one concurrent session

19 How? Your program Option 3: Use a slightly modified version of your existing Stata program in a web application. Statais a registered trademark of StataCorpLP, College Station, TX, USA, and the Statalogo is used with the permission of StataCorp.

20 How? Your program Option 3: Use a slightly modified version of your existing Stata program in a web application. --In this presentation, we will see how to build a web application/web service using your Stata program,, with minimal modifications based on Stata/IC, Stata/SE or Stata/MP. --Very similar techniques can be used with Numericsfor Stata. Statais a registered trademark of StataCorpLP, College Station, TX, USA, and the Statalogo is used with the permission of StataCorp.

21 Technologies Program core: Stata + Mata Web application language: PHP Web server: Apache Operating system: Windows

22 Technologies Program core: Stata + Mata Web application language: PHP Web server: Apache Operating system: Windows Well-known Easy to use

23 Technologies Program core: Stata + Mata Web application language: PHP Web server: Apache Open source Operating system: Windows Well-known Easy to use

24 Web application language PHP implementation example Other languages may also be used: - Java (servlets, JSPs) -Python -ASP / ASP.net+ C# / VB.net - C/C++, Perl (CGI interface) -et cetera

25 Web server Apacheimplementation example Otherweb servers, application containers and application servers may also be used: -Tomcat -JBoss - Oracle WebLogic - IBM WebSphere -Magic xpa -et cetera

26 Operating system It should be possible to do this on any operating systemthat that supports Stata (i.e. Windows, Unix/Linux, Mac OS X).

27 General idea Web interface (HTML / JS) Web application (PHP / Java / ASP.net + C# / etc ) Program written in Stata / Mata Web server / Application server Stata IC / SE / MP Operating system

28 Calling Stata Web interface (HTML / JS) Web application (PHP / Java / ASP.net + C# / etc ) Program written in Stata / Mata Web server / Application server Stata IC / SE / MP Operating system Stata command(s)

29 Getting a response from Stata Web interface (HTML / JS) Web application (PHP / Java / ASP.net + C# / etc ) images data files text files log files Program written in Stata / Mata Web server / Application server Stata IC / SE / MP Operating system

30 Simplified example

32 Calling Stata

33 Calling Stata <html> <head> Web interface </head> <body> <form action= call_stata.php" method="post"> Stata command(s):<br><br> <textarea name="stata_commands" ><br><br> <input type="submit" value="send command(s) to Stata" > </form> </body> </html>

35 Calling Stata call_stata.php <?php... $stata_commands = $_POST[ stata_commands ]; write_stata_do_file($stata_commands); execute_stata_do_file();... >

36 Calling Stata Our web application will execute: <path_to_stata path_to_stata>/ >/Stata.exe /q /e do commands.do commands.do (Stata User s Guide, section [B.5])

37 Calling Stata Our web application will execute: <path_to_stata path_to_stata>/ >/Stata.exe /q /e do commands.do commands.do We ll previously write our commands here $stata_commands

38 Calling Stata Our web application will execute: <path_to_stata path_to_stata>/ >/Stata.exe /q /e do commands.do commands.do We ll previously write our commands here Example: cd <path_to_temp_folder path_to_temp_folder> sysuse auto histogram price $stata_commands

40 Calling Stata Problem: modern versions of Stata will not work if called directly from a web server (SYSTEM user). Web application PHP: shell_exec() stata.exe /e /q Stata IC / SE / MP

41 Calling Stata Problem: modern versions of Stata will not work if called directly from a web server (SYSTEM user). Solution: wrapper + user impersonation Web application PHP: shell_exec() stata.exe /e /q Wrapper library Stata IC / SE / MP

42 Getting a response from Stata Web interface (HTML / JS) Web application (PHP / Java / ASP.net + C# / etc ) images data files text files log files Program written in Stata / Mata Web server / Application server Stata IC / SE / MP Operating system

43 Getting a response from Stata Our web application will execute: <path_to_stata path_to_stata>/ >/Stata.exe /q /e do commands.do commands.do We ll previously write our commands here Example: cd <path_to_ path_to_web web_folder _folder>/ >/img img/ sysuse auto histogram price, normal saving(graph01, replace) graph export graph01.png, replace Now our web application will be able to display <path_to_ path_to_web web_folder _folder>/img/ >/img/graph01.png graph01.png

44 Getting a response from Stata call_stata.php <?php... $stata_commands = $_POST[ stata_commands ]; write_stata_do_file($stata_commands); execute_stata_do_file(); display_results(); //display graph01.png png...?>

45 Getting a response from Stata call_stata.php <?php... function display_results() { echo <html> ; echo <head>result</head> ; echo <body> ; echo <img src=img/graph01.png graph01.png> ; echo </body> ; echo </html> ; }...?>

46 Getting a response from Stata

47 Basic security SQL injection attack: '; DROP TABLE users;

48 Basic security Prevent Statainjection attacks: --Limited, sanitized inputs, Ideally, no free text fields on the web interface --Avoid or restrict shell(), xshell(), winexec() in your Stata program

49 Basic security Bad practice Better practice

50 Basic security Prevent Statainjection attacks: --Limited, sanitized inputs, Ideally, no free text fields on the web interface --Avoid or restrict shell(), xshell(), winexec() in your Stata program

51 Basic security Bad practice Better practice

52 Basic security It s even better to avoid dynamic shell() commands if Stata is executed through a web interface Bad practice Better practice

53 Implementation examples

54 Web interface for coin Studying coincidences with network analysis and other multivariate tools Modesto Escobar. Stata Journal (in press)

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63 Web interface for nomolog A general-purpose nomogramgenerator for predictive logistic regression models ZlotnikA, AbrairaV. StataJournal Volume 15, Number 2 URL:

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66 In the web implementation, we must add a tab for loading the dataset and executing the logistic regression command.

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68 Questions?

69 Credits Special thanks to all the people who made and released these design resources for free: Presentation template by SlidesCarnival Photographs by Unsplash& Death to the Stock Photo (license)