I want to maintain state in my Perl web app. How can I do this effectively? I looked at CGI::Session but it says that it doesn't work well with UTF-8 pages, which is a requirement. I'd also like to be able to pass some basic information to another Java application running on the Glassfish app server, so people aren't forced to login to both apps, for example. How can all this be managed?
The basics of sessions are that you need a place to hold the session data (the store) and a way to store and retrieve the session data. While some frameworks call that The State, it really boils down to having a session key (or session ID) and passing it back to your app via either a cookie or a URL parameter.
Your store can be anything that can hold the data for you. Some examples are: a flat file, a dbm file, a DBMS,or an in-memory cache of some type.
The most common implementation, which is used by CGI::session and Apache::Session is to have three fields in each record inside the store: session_id,session_data, expires_time.
The session modules on the CPAN take care of loading your session at the beginning of the request, and storing it back at the end.
The bug referenced in the documentation for CGI::Session is marked as "resolved". That one was about utf-8 in the database.
It seems that you still should not use 'use encoding utf-8'. But why would you do that in the first place? "perldoc encoding" says "allows you to write your script in non-ascii or non-utf8". WTF?
Having your resulting HTML utf8-encoded does not seem to be an issue when using CGI::Session.
Find a Perl web framework that handles sessions for you.
For example Catalyst. It will completely abstract out user sessions so that you don't really even have to think about it. See a tutorial on how to use sessions with catalyst.
If you're programming a website in Perl, you should really be using this framework anyways.
Hm, if it is not too late.
CGI::Session works just fine with any data. It depends on the serialization format that you use for your session and how you store them in your database.
I would suggest also a combination with CGI::Simple for which I added UTF-8 form-data handling.
Is your connection to the database UTF-8 enabled?
for MySQL you can use:
SET NAMES UTF8;
as the very first statement after connecting;
Do you store store your session in a text field with some different encoding?
Just take a little care with such things and you will be fine.
You can look at some examples of usage here.
Your best bet would be to generate some sort of session key and store it in a cookie on the browser. Then, use that key to store information in either a database or memcached that both can access.
Related
There are several apps that I use on my Mac that store their data in core data. I can see the data I want in CoreDataPro. I want that data - specifically I want to send changes in that to some remote end points (such as Zapier, or some other REST service).
I was thinking of piggybacking something like RestKit - such that I provide a configuration file saying where the app is and what end points the data needs sending to. I need only to scrape the data and send to REST, not a two-way sync.
I'd prefer a utility that I could configure rather than having to code a Mac application.
I noted http://nshipster.com/core-data-libraries-and-utilities/ - RestKit still seemed the most capable, but in https://github.com/RestKit/RestKit/issues/1748 I was advised that coredata projects should only be opened by a single application at a time, and really RestKit is designed for baking into the source app (rather than for database scraping and sending).
What approach would you take?
I also noted:
http://www.raywenderlich.com/15916/how-to-synchronize-core-data-with-a-web-service-part-1
Thanks, Martin.
First, Core Data is an object store in memory. What is written to disk from Core Data can be in one of several formats. One of those formats happens to be SQLite. If the application is writing to SQLite then it is possible to sample that same file and push it somewhere else.
However, each application will have its own data structure so you would need to be flexible in the structure you are handling.
RestKit has no value in this situation as you are just translating objects into JSON and pushing them to a server. The built in frameworks do that just fine.
There is no utility to do this at this time. You would need to write it yourself or hire someone to write it.
If I were going to do something like this, I would write it using Core Data itself interrogate the model from the application that wrote the data in the first place and then translate the database into JSON and push it. You won't be able to tell what is new vs. old so the server will need to sort that out.
Another option, since you can't diff anyway, is to just push the sqlite file to the server and let the server parse through it.
Other answers might include:
use a middleware platform e.g. using rssbus.com (only) sqlite connections are free to send the events
as my target system (http://easy-insight.com) actually has a transmitter that sends new records it sees from MySQL abd PostgreSQL, I could https://dba.stackexchange.com/questions/2510/tools-to-migrate-from-sqlite-to-postgresql or use an ETL such as http://www.easyfrom.net (I did ask the vendor for SQLite support a long time ago, but SQLite is just not a priority for them).
I'm wondering whether a good answer (where good excludes Objective-C and includes languages that I do know, such as - to a limited extent - Ruby) is to use MacRuby and its Core Data libraries.
Core Data seemingly can be exposed as an Active Record. https://www.google.com/search?q=macruby+coredata , notably http://www.spacevatican.org/2012/1/26/seeding-coredata-databases-with-ruby/
However, MacRuby seems to have faded - https://github.com/MacRuby/MacRuby/issues/231 - it won't even compile on Mavericks.
I'm trying to find some reading materials on how to connect an IPHONE app to a central DB-Server such as SQL-Server.
I know about SQLite, and the other methods of storing Data in the device itself. What I'm really interested is for the application to interact with a central database server. Are there any sort of objects such as SQLClient in .net or do I need to go through sending off HTTP-Requests and deserializing json/xml?
i dont know the answer to your question, but even if you find that it would be not recommended to do so, since its always better to use an httprequest solution,
Encapsulating the database implementation is always the way to go, since database implementation could change rather quickly adding a layer over it is recommended
That goes without saying that you will not be able to do caching by accessing the database directly, which is also a drawback
am sorry this is not the answer you are looking for, but you should re think on how you are going to implement your solution,
Preform a httprequest to a php script or similar and parse JSON or XML.
You would have to make a REST interface to bridge the 2 together, and as you said deserialize responses depending on the format, if it's json or xml.
From Device side, make GET/POST requests to your script, which responds the query results back to the app and handle them accordingly.
I'm about to start an iOS project that requires pulling user's data from an SQL Database and viewing it within the App. Before I begin I'm looking for conformation that I'm taking the right (best) route.
My Plan:
App starts on login page (app will display data from another service)
App uses AFNetworking to post request to web service
Web service gets user data from SQL Database and sends back JSON
App uses JSONKit to parse the feed and load into Core-Data
App uses info from core-data to populate UI
Does this seem like an appropriate way to get the info into Core-Data from SQL? Any suggestions for doing things differently?
Thanks.
Are you receiving the response from the web server in JSON? If so, the fact that the server is using an SQL database is immaterial. What you need to know is how to parse JSON for inclusion in a core data store. Cocoa is my Girlfriend has a pretty good tutorial up.
Part 1
Part 2
To answer your comment, here's what I've done.
Display a login screen. The login credentials should be stored in the keychain for security. I've used SSKeychain for this.
To handle sending and receiving data from a web request your best option is to use a pre-built library. I've always used ASIHTTPRequest, but since it is no longer under active development, you should probably look around a bit before you commit to anything. I'm sure there are nicer and cleaner libraries out there.
You need to parse the JSON responses. I'm a fan of JSONKit. It's very fast, very easy to use, very robust.
Pulling data out of the core data store and displaying it in the interface will be no problem for you. If you create a new project in Xcode most of the setup will be done for you.
Now, there are a lot of projects out there that attempt to combine web requests, json parsing and core data loading into one framework. I've tried to use a few of these and haven't had much luck. The ones I've tried haven't been robust and very difficult to debug. Setting up your own request/parse/load code is not difficult at all, just a bit time consuming.
I am sure that there are a lot os ways to make implement this problem. Your solution is one of the popular solutions I guess but you could connect to the DB via a socket and talk with the database directly e.g. Going over a port 80 web site has the advantage that the possibility of some kind of firewall blocking the communication is very low. I would solve this kind of problem the same way I guess.
I'm trying to clone a commercial Student Management System which was written in Perl. I want to use PHP, as I have no experience in Perl.
I am now trying to set up the login system, which should be (has to be?) done with PHPSESSID's, right? Now, in PHP I could transmit the Session ID via GET, POST, and COOKIE.
The Perl website doesn't add parameters to the URL (GET) and does not save cookies on my computer (COOKIE). There is also no form which could contain a hidden field (which would be POST in PHP, right?)
Can someone tell me how Perl remembers the logged in user there?
Perl takes a much more "toolkit"-based approach to building web applications than PHP does, because Perl was not designed specifically for web work. So it doesn't have any built-in way of doing web app session management; rather, there are many modules on CPAN which implement session management in many different ways.
If you were to identify the Student Management System in question and provide a URL, we might be able to look at it from the outside and identify what it's doing, but, really, I question whether you actually need to use the same session management system as the existing app unless you want to implement single-sign-on between the original version and your clone[1]. Concentrate on cloning the user-visible interface and functionality rather than the implementation details behind it.
[1] ...which would be futile anyhow unless you're also planning to tap into its session database on the back end, since neither one will recognize the other's session ids if they don't share that data.
For the sake of completeness, there are OTHER, non-standard ways to store/transmit session information than the 3 methods you listed (although I seriously doubt any of them are used in your SMS). Among them:
Sending the cookie data as part of the DOM (e.g. in HTML) and having on-page JavaScript access it from DOM
Or, just store the cookied data as JavaScript's data in the first place.
AJAX calls. E.g. the session-enabled logic is all handled in AJAX URLs and not the main URLs. Yes, I know that's completely screwy. But doable.
Don't store the cookie in main cookie database (so you can't find it using standard cookie viewing methods). For details on how that's done, please google "evercookie" for a VERY cool method of persistently storing cookie info by utilizing up to 10 redundant storage options - one good intro is http://blog.depthsecurity.com/2010/09/super-persistent-cookies-evercookie.html
All that said, I completely agree with Dave's answer - just use PHP's best practices mechanism to implement the functionality instead of cloning possibly-perl-specific and possibly-weird implementation in the webapp.
I'm trying to make a page with 2 fields (email and feedback) and 1 button. When the user clicks on the button, a table on a page else where is filled in with the data, permanently.
Does anyone have recommendations of how I should do this? I'd like to avoid having a script send me an email, or writing to a database. But if I have to, which ever is easier to configure would be prefered.
Thanks,
Matt
So you want a comments system like you find on most blogs? You'll need to store those comments somewhere, probably in a database. As for how to do it, that would depend entirely on what you already know and what the site is currently written in. You could use PHP and MySql if you already have those skills, or ASP.Net/SQL Server, or if you want to be down with the cool kids you can use Ruby on Rails or Python/Django.
If you post what languages you already have experience in, and/or what the site is written in you might get a more specific answer :-)
There're 2 types of scripts: server side and client side. The client side script (JavaScript) stores info only for particular visitor on his computer and this can't be seen by anybody else.
You need a server side script to save feedback on the server. The language or technology depends on the hosting server you use. Not all hosting services allows server side scripts. You need first to find out what scripting languages and technologies are supported by your hosting provider. Then we can help you more.
ADD:
For an unexperienced persons I recommend to search for hosting services which has most needed functionality. Something like blogs, etc. On such services you could create pages that will have comments and feedback and many more.
While it may seem outdated it's not necessarily a bad design. You can use PHP or Perl (due to it's string parsing capabilities) and simply store the main page on the disk.
Here's your sudo code/design...
You'll need need an html page that looks as follows
<tr><td>email</td><td>comment 1</td></tr>
<tr><td>email 2</td><td>comment 2</td></tr>
<tr><td>email 3</td><td>comment 3</td></tr>
Then you'll need a php script page that will read this html file in and display it.
The php page will also contain code for dealing with a user submitted comment. When a user posts a comment you need to open the html page with the rows in it and append to that file.
You need to be careful with this design however because you may run into write concurrency issues if two people attempt to read the file at the same time. Add code to handle this gracefully accordingly.