I've looked around the site to see if there are any people who have changed the CKAN API interface so that instead of uploading documents and databases, they can directly type onto the site, but I haven't found any use cases.
Currently, we have a page where people upload data sets through excel forms that they've filled out, but we want to make it a bit more user friendly by changing the API so that they can fill out a form on the page rather than downloading the template, filling it out and then uploading it.
Does CKAN have the ability to support this? If so, are there any examples or use cases of websites that have use forms rather than uploads?
This is certainly possible.
I'm not aware of any existing extensions that provide that functionality, but you can check the official list of CKAN extensions if there's anything that fulfills your needs.
If there is no existing extension that suits you then you could write your own, see the extension guide for details on how to do that.
Adding an API function to CKAN's API is possible, but probably not what you want in this case: the web UI usually does not interact with CKAN via the API but via Flask/Pylons controllers. Hence, you would add your add controller which first serves your form and then processes the submitted inputs.
You can take a look at the ckanext-pages extension, which does exactly that (for editing static pages instead of datasets, but your code would be similar).
I often need to create similar, but very long HTML forms for a client. The forms contain some inter-dependent fields and lot of validations. Some images also need to be uploaded.
Then the client needs to check the database in the CPanel and export it from there.
I want to create something with easy interface which can create complicated forms. Also, client is asking for easy-to-operate back end. The CMS option looks like an overkill. I want to keep the site as lightweight as possible because of performance requirement.
Please suggest me the best path I should take. Should I try to develop everything from scratch? Should I use a CMS? Is there any particular CMS more suitable for the task?
We use ChronoForms along with Joomla 3.1 to create such forms. It has two modes, an easier one that limits the functionality but creation of forms is much easier. The other one offers the full capabilities of the engine but requires manual steps to do even simple things.
Having said that, ChronoForms is the most powerful web based forms designer I have come across. It seems they also support Wordpress now.
They have a drag-drop mechanism to design the forms. Validations are easy to do via check boxes for the standard ones. You can save the results into database tables, send emails, redirect users to specific pages, add captchas.
The backend allows you to view the records and create new tables based on the fields of the form. You can also export the result as CSV.
I was thinking about a building a CMS, and I want to implement the wordpress-like permalink for my posts. How do I do that?
I mean, How do I define the custom url structure for my pages?
What language are you using? I'm assuming that you are thinking about PHP (given your reference to word press). You have a few options:
Mod-Rewrite
Router
In my opinion, the best option is to find a modern web framework that provides good routing functionality. Furthermore, look at modifying an existing CMS (many exist; you seem to have heard of word press).
I'd recommend creating links that pass in a URL parameter such as ..."http://...PostID?123&CatID=232&..." so that when the person clicks on that particular link, you can parse the parameters in the URL, and get the exact post based on id, or even do further filtering by passing in other fields as needed.
If you want to build the whole thing yourself, first understand what a front controller is, as it really addresses the underlying issue of how do you execute the same code for different URLs. With this understanding, there are two ways to attack the problem with this design pattern: URL rewriting or physical file generation.
URL Rewriting
With URL rewriting, you would need intercept the requested URL and send it onto your front controller. Typically this is accomplished at the web server level, although some application servers also act as web servers. With Apache, as others have posted, you would use mod_rewrite with a rule that looks something like this:
RewriteRule ^/(.*) /path/to/front/controller.ext [E=REQUEST_URI:%{REQUEST_URI},QSA,PT,NS]
With this rule, the path originally requested with be sent to the front controller as a variable called "REQUEST_URI". Note, I'm not sure the right syntax in PHP to access it. In the front controller hash (e.g. MD5) this value and use it to lookup the record from a database - take into account whatever hashing algorithm you use will produce duplicates. The hash is necessary if you allow URLs over whatever the max column size is in your database for varchar data, assuming you can't search on CLOBs.
Physical File Generation
Physical file generation would create a file that maps to the permanent URL you're imagining. So you'd write something that creates/renames the file at time it's posted. This removes the need for storing a hash and instead you place information about the post you want to serve inside that file (i.e. ID of the post) and pass that along to the front controller.
Recommendation
My preference is the URL rewriting approach, so you don't have to worry about writing dynamic code files out at runtime. That said, if you want something with less magic, or you're expecting a lot of requests, the physical file generation is the way to go because it's more obvious and requires the server to do less work.
I'm planning my first iPhone app and I'd like to get some inputs as to how to build it, right from the start. The iPhone app is being built to be paired with a public facing web application that is already built in PHP.
I'd like the web platform to be central (data is housed in a mySQL database), and have the
iPhone clients talk to it and use REST'ful methods to perform the functions of the site
(fetching latest content, posting content, voting, account management as examples).
I'd like the clients to get a local copy of the data in a SQLite database, but refresh to get the latest version of the feed (similar to the Twitter app).
Couple of thoughts I have right now:
Use something like ASIHTTPRequest to send/recieve data to PHP files on the server listening for requests
JSON - would I be better off to send the GET/POSTS to a PHP that returns JSON objects, and work with some sort of wrapper that manages the data and communicates changes to the local SQLite database?
Am I totally off in how I should be building this thing to communicate with the web? Is
there a best practice for this?
I'd really appreciate any input on how you would architect this sort of a setup.
Thank you,
EDIT: After reading my own post again, I know it sounds like a Twitter client, but it is NOT, although it has similar features/structure of a Twitter type setup. Thanks!
As you already outlined in your plan, XML and REST are a great way to communicate with a web application. I want to suggest few details about how to actually design and build it, or what you should keep in mind.
First of all, I believe it's important to stick with MVC. I've seen people creating HTTP connections in view-controllers, controllers being NSXMLParser's delegate, controllers containing data in member variables. I've even seen UITableCells establishing HTTP connections. Don't do it!
Your model and its basic manipulation code should be as much extracted from user interface as possible. As you already have created the model in your web-application, try to recreate the entities in your iPhone project. Don't be afraid of having some simple methods in entity classes, but do not make them use external resources, especially tcp connections. As an example of methods in entity class you might have methods that formats data in specific ways (dates as an example, or returning fullname as concatenation of firstname and surname), or you can even have a method like - (void)update that would act as a wrapper to call class responsible to update the model.
Create another class for updating the model - fetching the XMLs from web-app. Do not even consider using synchronous connections, not even from a dedicated thread. Asynchronous connections with delegate is the way to go. Sometimes multiple requests need to be made to get all required data. You might want to create some kind of state-machine to keep the information about in which stage of downloading you are, and progress from stage to stage, skipping to the end if error occurs, re-executing from failed stage after some moments.
Download data somewhere temporarily, and first when you have it all, make a switch and update user interface. This helps responsiveness during launching the app - user gets to work immediately with data stored locally, while the update mechanism is downloading the new data.
If you need to download lots of files, try to download them simultaneously, if dependencies between files allow for that. This involves creating a connection per request, probably delegate instance for each of them. You can of course have only one delegate instance for all of those connections, but it gets a bit more complex to track the data. Downloading simultaneously might decrease latency considerably, making the mechanism much faster for the user.
To save the time and bandwidth, consider using HTTP's If-Modified-Since and/or ETag headers. Remember the time or tag when you requested the data the last time, and next time send it in HTTP's header. Your web-application should return HTTP code 304 if content has not been changed. iPhone app should react on this code accordingly in connection:didReceiveResponse:.
Create a dedicated class to parse the XML and update the model. You can use NSXMLParser, but if your files are not huge I strongly recommend TouchXML, it's such a pleasure to work with XML as document (it also supports XPath), instead of an event based API. You can use this parser also when files are downloaded to check their validity - re-download if parsing fails. That's when dedicated class for parsing comes handy.
If your dataset is not huge, if you do not need to persist downloaded data on iPhone forever, you probably don't need to store them in SQLite database, you can simply store them in XML format - just a simple caching. That at least might be the way for a twitter app. It gets easier that way, but for bigger data sets XML consumes lots of memory and processing power - in that case SQLite is better.
I'd suggest using Core Data, but you mention this is your first iPhone app, so I suggest you don't use it. Yet.
Do not forget about multitasking - your app can go to sleep in the middle of download, you need to cancel connections, and cleanup your update mechanisms. On app's wake-up you might want to resume the update.
Regarding the view part of the application - use Interface Builder. It might be painful in the beginning, but it pays off in the long run.
View controllers are the glue between model and views. Do not store data in there. Think twice about what to implement where, and who should call it.
This is not related to architecture of the app, but I want to remind that Objective-C is very expressive language. Code should read much like a sentence. Extend classes with protocols. As an example the other day I needed first line of a string. Sure, you can write a one-liner where you find first occurrence of a new-line, and get a substring from beginning till there. But it doesn't look right. I've added - (NSString*)firstLine into my NSString's protocol. Code looks so much better this way, it doesn't need any comments.
There are lots of things to consider in both architecture and design of any project, they both should go hand in hand. If one is causing trouble to the other, you need to adapt. Nothing is written in stone.
I'm currently working on an app that sounds similar to yours. I'd also suggest ASIHTTPRequest, and probably something like TouchJSON for JSON parsing, or extending/making a delegate of NSXMLParser if you want to parse XML.
As suggested by JosephH, depending on how your app works you may want to consider alternate authentication methods: I'd take a look at something token-based like OAuth, which has ready-made libraries for people to dig in to.
SQLite is totally viable for feed caching, although I prefer NSCoding so that you can freeze-dry your custom data structures.
As a general suggestion, make sure to spend a lot of time thinking about every use case and corner case for connections: it's easy to assume a user will only contact the server in certain ways and at certain times, and then after you throw in multitasking/incoming calls/lock screen/memory warnings, things can get hairy without any planning.
All in all, you seem to be on the right track, just make sure you plan out everything beforehand :)
Apple have a brand new in depth piece of sample code - MVCNetworking that shows in depth how to use subclasses of NSHTTPRequests and NSOperationQueues.
As others mentioned, I think you are asking the right questions and are heading in the right direction. All of the replies above are valuable advice. Here is my advice, and I hope you'll find it useful.
No matter which method/library you choose to talk to your web services, I think it's important to make a clean separation in the way you design your data model on the phone VS. the data model in your web application. You have 3 major distinctions to keep in mind for your design:
Data model on the web application (reflected by your existing mySQL database)
Since this is already there, there is not much to say about it, except that it will influence a lot your design for the following 2 parts. I suggest to make this model the 'master reference' for how your data is represented across platforms.
Data model on the iPhone app (reflected by the information you need to display in the iPhone app)
This is where the fun begins. First, you need a good understanding of what data you need to display in the phone app. So have a good, high level design of your app first (use pen and paper, draw mock-ups of each view and the interactions between them, model the navigation between your view controllers etc.). It really helps to understand the interactions between your view controllers and the various bits and pieces of data you want to show in the app. This will help you create the requirements for the data model on the phone. Based on these requirements, map the existing (web) data model to a new model, suited to your iPhone app. This new model may or may not include all tables and fields found in your web app. But the general representation of the 2 models should be very similar (e.g. relationships, data types, etc.)
Data model used to communicate between the 2 above (this is your 'data exchange protocol')
Once you have the 2 representations of your data above, you need to 'translate' from one to the other, both ways. Design your data exchange protocol to be as simple and compact as possible. You don't want to waste bytes on useless information, as transmissions over the network are costly. (As a side note, you might think of compressing the transmitted data later on, but it's just as important to have a good design from the beginning). It's probably best to begin with a protocol in which the metadata is the same as the one in your web application model (e.g. same relationships, names of tables, attributes, etc.). But remember, you'll only have to serialize/de-serialize those entities and relationships that you listed in point 2) above. So design accordingly. Your exchange protocol may also include session tokens, authentication info, a version number, or other metadata, if you need it.
Remember: your data exchange protocol is what will de-couple your web application and iPhone application models. I found that it's best to de-couple them because they may both evolve over time. The data model on the iPhone for example, may evolve a lot especially when you will find that you need to re-model some relationships or add/remove attributes from your entities in order to improve application responsiveness, or the user experience, the navigation, or whatever.
Since this is a whole concern in and by itself, well, you need to design a generic serialization/de-serialization mechanism on top of your (JSON/XML/whatever parser you choose) that is flexible enough to sustain the potential differences between your 2 data models. These differences might be: entity/attribute/relationship names, primary key identifier names, data types, attributes to ignore, and the list goes on. I would definitely implement a serializer/de-serializer utility class in the iPhone app, backed by a .plist configuration file containing all supported entities, concerns, aliases you might have. Of course, each model object should 'know' how to serialize, de-serialize itself and its relationships (i.e. the required object graph depth).
One last note, since you will end up with 2 representations of your data, you will need a way to uniquely identify an object on both sides. So for example, think of adding a uuid attribute to all data that needs to be exchanged, or use any other approach that suits your needs.
I am building an app that has similar requirements to yours, and these are the approaches I found to be best so far. Also, you might find this video useful (it inspired me a lot on how to implement some of the issues I mentioned above and is especially interesting if you're using CoreData) :
http://itunes.apple.com/ca/podcast/linkedin-important-life-lessons/id384233225?i=85092597
(see the lecture entitled "LinkedIn: Important Life Lessons on CoreData & GameKit (March 12, 2010)" )
Good luck!
It's quite a broad question, and I think you're going in the right way anyway, however I'll do my best to give some advice:
JSON, ASIHTTPRequest and POSTs to PHP scripts sound like a great way to go.
If the data is not really sensitive, I'd use http most of the time, and use https only for a login page that either sets a cookie or returns a "token" that you use in subsequent requests. (HTTPS can be quite slow over a 3G connection as the overhead in terms of number of packets to setup an SSL connection is higher than a plain TCP connection.)
You should make sure you correctly pass any data from the input to the PHP scripts to the database, to avoid any SQL injection attacks - ie. used parameterised SQL, don't create sql queries by doing "SELECT * from users where username="+$_GET['username']"
I would do this like I have done with a lot of AJAX web-page stuff. i.e.:
Have a URL on your server side package the information to be transmitted into XML format. (This can be through a CGI/PHP script or whatever). Your transmitting XML in the message body - so it's easy to human read and debug with a standard web browser.
Use the standard iPhone NSXMLParser methods to parse out the individual data fields from the XML doc, and write it back to your database. This method is equiped to both fetch the data from a URL and parse it in one call - like:
NSURL *xmlURL = [NSURL URLWithString:#"http://www.example.com/livefeed.cgi"];
NSXMLParser *myParser = [[NSXMLParser alloc] initWithContentsOfURL:xmlURL];
Walk through the data hierarchy with the NSXMLParser methods and populate your database accordingly.
I'm considering Wordpress as my CMS platform for a client site I'm doing at the moment.
However, I need to create a couple of custom 'modules'. One of these modules is a form that people will be able to complete and have a quote, and once submitted, in a special place in the Wordpress panel (like a menu or something), there will be a listing of all the submitted quotes (just fetching it from a table in my database).
Another one is to manage a cafeteria menu, so the client can add a different meal to each day of the week.
I know perfectly how to do this kind of things using some kind of MVC framework and doing it 'by-hand', but I'm just wondering if this would be possible to do with WP and if yes, what kind of tools I'll have to use.
Thanks
Quite simply, yes, WordPress would be a more-than-capable asset to your criteria. But it's whether the learning curve in getting to know WP outweighs using a framework you're clearly already familiar with?
Personally, it sounds you like you're pretty solid with PHP, and considering the fact that, in my opinion, what you're planning on doing is relatively easy, I'd say WordPress is an excellent solution.
I'd recommend reading about WordPress 3.0's new custom post type API, and skimming the basics of hooks and filters in the Plugin API.
Submitted quotes would merely be a custom post type. You'd be better off writing the front-end code (like handling the form, UI etc.) yourself, either within a theme or plugin, then using wp_insert_post and let WordPress handle all the database administration. In fact, WP will go one step further and set up the entire admin for viewing, editing and deleting quotes.
Post meta (also known as custom fields) is also there for you if you need to store additional information about a quote that doesn't quite fit the post's table structure.
For the menu, this is even easier. I'd say just create a post category called 'Menu', and the client can publish 'dishes' to it as you would with a blog or any similar rolling format.
I've only licked the surface here. Get stuck in with the above, then check out some other goodies like meta boxes and custom taxonomies!
If you want to try a plugin instead of writing something yourself, Flutter might work. It's a little unpolished sometimes but it makes this sort of thing an absolute breeze.