I want to developp a rest API using loopback.js, which seems to be a good solution, but my case is a bit special.
my rest api must serve differents projects: for example:
http://mydomain/project-1/api/documents
http://mydomain/project-2/api/documents
http://mydomain/project-3/api/documents
each of my projects (project-1, project-2) have more or less the same core structure (a "document" table, a "article" table, etc...)
each of my projects must inherit this core structure but can expand it with fields, models, ...
I thought I could use loopback.js to define a core description of my database, and extend my descriptions using inheritance for instance to describe instance projects database, and choose the right database/models to use on the flight.
Three questions so:
Do you think loopback.js is the right nodejs solution to do so or is there a better option?
is it possible to create a core definition of my base/models and extend it for each project, only dedefining what is différent?
how and where would you set the database/models to use on the flight by parsing the url and having the same api serving all my projects?
It is a loopback.js newbie question, but I can't find any other question/response on the subject. If you having any example of something similar in nodejs, I would be gratefull!
Thanks a lot!
Pierre.
Related
Spring Security uses UserDetailsManager to manage users & authorities.
I want use same implementation JdbcUserDetailsManager to manage user page by admin (user CRUD, managing groups, pagination). But unfortunately there is no implementation for paging, manage groups and so on.
So I've got an issues:
User CRUD because of json convertation for REST.
Group CRUD because of json convertation for REST.
User paging because of UserDetailsManager has no correspond implementation.
Group paging - no implementation.
User JSON to POJO (for create\update operations could be used UserDetails has implementations InetOrgPerson, Person, User but... i've got json convertation issue, can not mark classes with #JsonIgnore).
User POJO to JSON (for read operation i can not remove from data any important fields (for example: password)).
All of this issues have few solution ways:
1.1. Create one more user object similar to User, add expected JSON annotations OR in rest controller create builder to build User object from input parameter map (builder is good pattern by i think this is ugly way to manage something if it was implemented once)
1.2. add spring-datajpa repository (duplicates some security part of JdbcUserDetailsManager) OR extend from JdbcUserDetailsManager and add unimplemented part to manage users, groups...
Solution is the same with 1.
If 1. implemeted using spring-data-jpa - no problems, other case it needs to implement correspond factory builders to provide paging in dynamic way.
Solution is the same with 3.
Solved on 1., 2. steps.
Solved on 1., 2. steps.
Which solution way i should follow (implement managers spring-data-jpa based with additional POJOs or expand functionality for JdbcUserDetailsManager) ?
Describing situation, i think i'll implement solution using spring-data-jpa and extra POJO-entities to have all CRUD and JSON manipulating abilities. This way seems better saving implementation time, and code will be more cleaner for support generation.
If i mistook in my choice, let me know please. also please let me know if my issues already solved in spring (sorry i did not find solutions for described issues). Also i believe someone wants other solution architecture - i would discuss or consider clever ideas.
I am new to spring mvc. I have a lot of doubts to be cleared before i can continue.
I want to create a simple application wherein an employee details such as name age phone etc is entered and through ajax call the form data has to be to sent to server using json. For server side i am using spring. And the submitted data has to be shown in a jquery data table. And again to retrieve data an ajax call has to be used to get the data as a json. And no binding tool like jackson should be used.
1.) how do i go about creating an application in eclipse. If i should do a simpel java project or a dynamic web project?
2.) Could any one pls provide a sample code of each of the steps.
Thank you in advance
First, I think it's easier to start with Maven, create a WAR project, and use that to generate the Eclipse project files, which you can then import. This has the advantage of allowing Maven to not only create the correct folder structure, but also let it manage your dependencies. There are plugins for Eclipse that help you work with Maven, and you should be able to find lots of How-Tos using Google. Otherwise, you would have to create a project type that generates the WAR, one of which I believe is a Web Project, and layout the folder structure manually.
After you have the proper folder layout, you will need to setup your web.xml to enable Spring, add your Java classes and view files (html, jsps, whatever), and build a WAR. The final step would be to deploy that WAR to a web container of some sort, like maybe Tomcat or Jetty. You can ether run it externally, or configure Eclipse to deploy and launch your WAR in the IDE directly. I prefer the latter approach, as it makes it easier to setup debugging, not that running it external makes it impossible.
In addition, I would recommend adding the Spring pluggins to Eclipse, or just download their STS (Spring Tool Suite), which is just Eclipse with all the Spring plugins already added and configured. STS has the bonus of already having tcServer available, which is Spring Source's flavor of Tomcat. Again, loads of how-tos available on how to do all of this.
Edit to answer first comment
I don't know if I can address your comment here fully, as it's a very broad request. You are basically asking how do I write a full application using jQuery and Spring MVC. The volumes of books dedicated to this subject, as well as many websites you could visit that give tutorials on how to start developing. In fact, I think the Spring website has a tutorial for building their demo Pet Clinic site using Spring MVC. What I will try to do is give you some direction on what you should be asking.
Spring MVC, as the name suggests, is a Model-View-Controller framework that leverages the Spring Framework. I will not attempt to go into any great detail, as again there are volumes of books out there on the subject of Spring and all its wonders, but in general Spring MVC wants an application broken into the following chunks:
1. The Model
These are the objects you are using to represent your "data". This can be data from a Database, flat file, some other web service call, or maybe just passed around in your Controller. You will hear them commonly referred to as domain objects or entities to name a few. But, no matter how you refer to them they are typically POJO (Plain Old Java Objects) Java Beans with no real business logic, who's only existence is to represent some "data" and how it relates to other "data".
Some people prefer to have this object know how to read/write itself to its data store, some people like to have an external object that is only used to handle the read/writes. These are sometime referred to as a DAO (Data Access Object) or a Repository. There are also frameworks you can use for dealing with this stuff, like Hibernate or JPA for databases.
2. The Service Layer
This isn't represented in the MVC acronym, and one might argue this is part of the "Controller", but it's usually a good idea to put your business logic into a service layer. This is typically a POJO class that has methods to do the things you need to do with your Model objects. It houses your business logic so all the business rules are in one place. These are usually split to represent business functions. For instance, if you had an application dealing with car purchases you might have one service class to deal with the User related functions (create a user, update a password, get his preferences), one to deal with inventory (what is in stock, what is on its way, what is the current sales price), and one to deal with making a purchase (validate the customer's credit, start the tag process, etc). Its also common for these services to have reference to each other. For instance, the User service above might use the Inventory service to get a list of VIN numbers for cars Bill sold last week.
3. The Controller
The controller is what glues the "view" to the service layer. It provides the mapping of the URLs in your app to the function(s) they perform in the service layer. Most people try not to clutter the Controller object with too much code, and try to push as much down into the Service layer as they can. But, as long as it's simple logic I personally don't mind having a tad bit of code in the Controller.
4. The View
This is what you are sending to the user. It may be a web page backed by a JSP. It may be an Excel spreadsheet report generated from user input. It may be a simple JSON response to a REST call. It's sort of "the sky's the limit" here. But, for the most part this is either a JSP view or a JSON or XML response from a web service call.
Now to address your comment more directly...
Since you are a novice, I would recommend one of 3 approaches:
Go get a book...do what the book says to do. There are tons out there. Find one that has a good walk-through of a project, and copy/paste their procedures. A good book will usually have a chapter on how to setup all the necessary tools (Eclipse, Tomcat/Jetty, etc)
Find a good how-to on the Internet. There are lots of people that have tutorials. Find one and copy/paste their procedures.
Use something like Spring Roo. Spring Roo is a code generation tool that can be used to build a fully working site with little to no code. I am a big fan of Roo, especially for lone developers not working in a team, as it can generate a TON of the boiler plate code most developers hate to write. It also does things in a very Spring-like fashion, since after all it was created by the Spring folks.
These will get you past the "how do I create the project in Eclipse" problem. Part 2 of question one is a little more tricky. I would say, for now, don't focus on AJAX and stuff. Focus on simply understanding how Spring MVC works. The problem is, you are basically trying to cram 10 things down at once. Spring MVC is hard enough to get your head wrapped around (the annotations, JSTL, EL, and the Spring custom tag libraries, not to mention all the other things you will probably be touching like Spring Data, etc), but then you want to add dynamic web pages, which is JavaScript (and most likely some framework like jQuery), and to cap it off you don't want to use anything like Jackson (not sure why, but ok...) to help ease the transition from Java to JavaScript. That's a tall order. Again, I would cut out AJAX/JavaScript stuff at first, get a good handle on how a SIMPLE application is built, and then you can jump into all the dynamic stuff.
For the last question, providing code samples, I would point you to mkyong's fantastic blog full of Spring-related tutorials as well as Spring's own Tutorial site and Spring's Sample site as a good starting point.
I tried out EF back in .NET 3.5 SP1, and I was one of the many who got frustrated and decided to learn LINQ to SQL instead. Now that I know EF is the "chosen" path forward, plus EF 4.0 has some exciting new features, I'd like to migrate my app to EF 4.0.
Can anyone suggest any good resources that are specifically targeted towards 4.0 and L2S migration? NOTE: I can find plenty of blogs and articles related to migrating from L2S to EF on .NET 3.5, but I feel like many of those were obviously dated and unhelpful to someone using 4.0.
I'd really like as much deep, under-the-hood stuff as I can get; I want to really come away feeling like I know EF 4.0 the way I currently know L2S 3.5.
TIA!
I have done loads of this very type of conversion and FWIW, I would say there are more similarities than differences. I don't think there is any definitive documentation that will make you feel like an expert in EF4, beyond the stuff that is already out there...
http://msdn.microsoft.com/en-us/library/ex6y04yf(VS.100).aspx
What I can give you are the more obvious "gotchas." Specifically, Linq2Sql wanted to combine the business layer and the data layer a lot more obviously. It really pushed you to create your own partial classes. I could go on and on about way, but the most specific reason is the way the one-to-one mapper will create public parent and child properties for all relations.
If you attempt to use any type of serialization against this model, you will like run into circular reference problems as a serializer moves from a parent to a child and then back to the parent as the Linq2Sql serialization behavior automatically includes all children in the graph. This can also be really annoying when you try to grab a customer record to check the "Name" property and automatically get all the related order records included in the graph. You can set these parent and child navigation properties to be either "public" or "internal" which means if you want access to them, but don't want the serializers to automatically create circular references, you pretty much have to access them in partial classes.
Once you start down the partial class path you generally just continue the pattern and eventually will start to add helper methods for accessing your data into your individual entity classes. Also, with the Linq2Sql DataContext being more lightweight, you often find people using some kind of Singleton pattern or Repository pattern for their context. You don't see this as much at all with EF 3.5 / 4.
So let's say you have some environment similar to the one described and you want to start converting. Well, you need to find out when your DataContext is going to be create/destroyed...some people will just start each Business Layer method with a using() statement and let the context pretty much live for the lifetime of the method. Obviously this means you can get into some hairy situations that require adding .ToList() or some other extension method to the ends of your questions you can have a fully in-memory collection of your objects to pass to a child method or whatever and even then you can have problems with attempting to update entities on a context that they weren't originally retrieved from.
You'll also need to figure out how to much of the BusinessLogic incorporated in your Linq2Sql partial classes out into another layer if it doesn't deal explicitly with the data operations. This will not be painless as you figure out when you need/don't need your context, but it is for the best..
Next, you will want to deal with the object graph situation. Because of the difference in the way lazy-loading works (they made this configurable in EF 4.0 to make it behave more like Linq2Sql for those who wanted it) you will probably need to check any implied uses of child objects in the graph from your Linq2Sql implementation and verify that it doesn't now require an explicit .Include() or a .Load() to get the child objects in the graph.
Finally, you will need to decide on a serialization solution in general. By default, the DataContracts and DataMember attributes that are generated as part of an EF model work great with WCF, but not at all great with the XmlSerializer used for things like old .asmx WebServices. Even in this circumstance you might be able to get away with it if you never need to serialize child objects over the wire. Since that usually isn't the case, you are going to want to move to WCF if you have a more SOA, which will add a whole new host of opportunies, yet headaches.
In order to deal with the partial classes situation, and the hefty DataContext and even the serialization issues, there are a number of new code-generation templates available with EF 4.0. The POCO-Entity template has a lot of people excited as it creates POCO classes, just as you'd expect (the trouble is that excludes any class or member attributes for WCF etc etc). Also, the Self-Tracking Entities model pretty much solves the context issue, because you can pass your entities around and let them remember when and how they were updated, so you can create/dispose your contexts much more freely (like Linq2Sql). As another bonus, this template is the go-to template for WCF or anything that builds on WCF like RIA Services or WCF Data Services, so they have the [DataContract], [DataMember], and [KnownType] attributes already figured out.
Here is a link to the POCO template (not included out of the box):
(EDIT: I cannot post two hyperlinks, so just visit the visualstudio gallery website and search for "ADO.NET C# POCO Entity Generator")
Be sure to read the link on the ADO.net team blog about implementing this. You might like the bit about splitting your context and your entities into separate projects/assemblies if you fall into the WebService vs. WCF Service category. The "Add Service Reference..." proxy generation doesn't do namespaces the same way "Add Web Reference..." used to, so you might like to actually reference your entity class assembly in your client app so you can "exclude types from reference libraries" or whatever on your service references so you don't get a lot of ambiguous references from multiple services which use the same EF model and expose those entities...
I know this is long and rambling, but these little gotchas were waaay more of an issue for me than remembering to use context.EntityCollection.AddObject() instead of context.EntityCollection.InsertOnSubmit() and context.SaveChanges() instead of context.SubmitChanges()...
For EF Code First, it's mostly about reverse engineering the existing tables into EF classes. EF Power Tools now does this for you:
http://msdn.microsoft.com/en-us/data/jj200620.aspx
The rest is the obvious work of modifying your existing code to use those generated classes to talk to the database instead of LINQ to SQL.
I'm trying to find a way to generate Linq to SQL classes with bi-directional serialization attributes. Basically I want a DataMember tag (with an appropriate order) on every association property, not just the ones where the class is the primary key (like the Visual Studio generator and SQL Metal do). I checked MyGeneration, but didn't really find anything that worked for me. I thought the T4 Toolbox was going to be my solution, it would be quite easy to modify it to add the attributes, but I get an exception on the calling side of my WCF service, and I've gotten no response back on the issue. I'm about to try installing CodeSmith and using PLINQO, but I'd prefer something free.
I'm pretty close to just writing my own T4 generator, but before I do that, I was hoping to find an pre-built solution to this rather simple problem first.
I ended up writing my own code generator for our L2S classes. We actually generate two sets of classes. One is a "lightweight" set of entities for client application use. These classes have no L2S plumbing. But they have the full datamember attributes with proper order. Then we have our L2S entities, which are strictly for backend use. This has worked out quite well.
Be careful using PLINQO. I've looked at that product extensively. In fact, much of my code generator is based on the code PLINQO generates. However, they have a "major flaw" (their words) in how they have implemented many to many relationships.
You might want to also look at a product named "Reegenerator".
Randy
This turned out to be the solution to my problem. I had just resigned myself to start researching my own generator when I stumbled upon that. It has a bidirectional serialization option and it works great! Here's a link to the author's bog, which contains a great video example of how to get started.
I am using Flex Builder 3 to develop my first application that will communicate with a server that has many operations, so many in fact it is overwhelming and I am grouping them together into classes that will expose the operations and also manage some client side meta data. I am calling these classes "server proxies" because they are technically similar to a proxy class in WCF. I would want to organize these classes where I can do things like the below where Authentication is a class, and ServerProxies is some feature of the language that allows me to group that class with other classes in the ServerProxies category, or subcatagories such as the Geography subcategory:
ServerProxies.Authentication.AddLoginSuccesfulListener(onLoginSuccessful);
ServerProxies.Authentication.SubmitCredentials(someParaemetersHere);
ServerProxies.Geography.Querying.GetAllTiles(someMoreParameters);
ServerProxies.Geography.Querying.MeasureTwoPoints(pointA,pointB);
ServerProxies.Geography.Display.RenderMapExtent(topLeftPoint,bottomRightPoint);
This example is kind of trivialized because some of these operations probably wouldn't go through a server, but that is not the topic at hand. (just had to say that before someone gets off on a tangent and flames me over some imaginary code)
*So my question is, what language feature of Action Script 3 would allow me to create such categories?
In C# it would have been a namespace, but namespaces in Action Script seem to be more like custom access modifiers that apply to methods and properties, rather than entire classes.
You have to use packages, in preforms the same task as namespaces in C#.
You can read more about it here:
http://www.foundation-flash.com/tutorials/packages/