In my application many classes have common field 'company'. When application saves that objects, they must be filled with company (there is validation for that). Company is also kept in a session. Now, when I want to use domain class as a command object, company must be already filled or I get validation error. Is there any way to always fill company field, before any validation happens, so that I didn't have to do it manually every time.
(I tried custom data binder, but it does not work when there is no parameter in a request)
You could set the property just before the object is saved, updated or validated using the GORM events beforeInsert, beforeUpdate or beforeValidate.
In your domain you need something like that:
import org.springframework.web.context.request.RequestContextHolder
class Foo {
String company
...
def beforeInsert = {
try {
// add some more error checking (i.e. if there is is no request)
def session = RequestContextHolder.currentRequestAttributes().getSession()
if(session) {
this.company = session.company
}
} catch(Exception e) {
log.error e
}
}
}
If you want to bind a property before the process of binding, You can create a custom BindEventListener and register in the grails-app/conf/spring/resources.groovy
First of all, create your custom BindEventListener
/src/groovy/SessionBinderEventListener.groovy
import org.springframework.beans.MutablePropertyValues
import org.springframework.beans.TypeConverter
class SessionBinderEventListener implements BindEVentListener {
void doBind(Object wrapper, MutablePropertyValues mpv, TypeConverter converter) {
def session = RequestContextHolder.currentRequestAttributes().getSession()
mpv.addPropertyValue("company", session.company)
}
}
Second of all, register your BindEventListener
grails-app/conf/spring/resources.groovy
beans = {
sessionBinderEventListener(SessionBinderEventListener)
}
However, if your domain class does not hold a property called company, you will get InvalidPropertyException. To overcome this issue, create a list of classes which contain a property called company - See details bellow
/src/groovy/SessionBinderEventListener.groovy
import org.springframework.beans.MutablePropertyValues
import org.springframework.beans.TypeConverter
class SessionBinderEventListener implements BindEVentListener {
private List<Class> allowedClasses = [Foo]
void doBind(Object wrapper, MutablePropertyValues mpv, TypeConverter converter) {
if(!(allowedClasses.contains(wrapper.class))) {
return
}
def session = RequestContextHolder.currentRequestAttributes().getSession()
mpv.addPropertyValue("company", session.company)
}
}
Related
I have an ASP.NET website project that until recent had all code in App_Code folder. It uses Entity Framework 4 as ORM. Application is divided into three "sections" (let's say one for each customer). Each section has it's own database (but same schema). This is due to performance reasons, databases are over 10GB each with millions of rows.
Each time a context object is created a Session variable which holds section ID is called and proprietary connection string is chosen for this context.
It looks like this (following are members of static Connection class):
public static MyEntities GetEntityContext()
{
if (HttpContext.Current.Session["section"] == null)
{
HttpContext.Current.Response.Redirect("~/Login.aspx");
}
var context = new MyEntities(GetEntityConnectionStringForSection((int)HttpContext.Current.Session["section"]);
return context;
}
private static string GetEntityConnectionStringForSection(int section)
{
switch (section)
{
case 1: return ConfigurationManager.ConnectionStrings["entity_1"].ConnectionString;
case 2: return ConfigurationManager.ConnectionStrings["entity_2"].ConnectionString;
case 3: return ConfigurationManager.ConnectionStrings["entity_3"].ConnectionString;
default: return ConfigurationManager.ConnectionStrings["entity_1"].ConnectionString;
}
}
It works very good and also handles situation when session timed out everytime any data access is performed.
Recently as I needed to share DB classes among two websites I moved all DB classes to separate class library and referenced System.Web library which I know is bad practice, but it's working.
Now the next step is to include unit and module tests which as I read is very difficult or impossible when using HttpContext in library, so I want to get rid of System.Web references. What is the best practice for this situation?
I think I can't just pass HttpContext to GetEntityContext() as it is also called from within my entity classes. Although this probably can be refactored. So maybe this is where I should go?
I also wondered if is it possible to somehow pass current section ID to this whole library? It cannot be just static property because as far as I understand it would be common for all users using the application. This should be user-specific.
Reassuming the objective is to make automated testing possible without loosing transparent Connection String choosing and session timeouts handling.
If I do something fundamentally wrong at this stage please also let me know. I can look again at this question tomorrow morning (8.00 am UTC) so please don't be discouraged by my silence till then.
EDIT:
Example of usage of Connection class in the library:
public partial class Store
{
public static List<Store> GetSpecialStores()
{
using (var context = Connection.GetEntityContext())
{
return context.Stores.Where(qq => qq.Type > 0).OrderBy(qq => qq.Code).ToList();
}
}
}
You can declare interface IContextProvider inside your library ans use it to retrieve context. Something like:
public interface IContextProvider
{
MyEntities GetEntityContext();
}
This will make your library testable. In your web project you can inject IContextProvider implementation into your library.
public class WebContextProvider : IContextProvider
{
public MyEntities GetEntityContext()
{
if (HttpContext.Current.Session["section"] == null)
HttpContext.Current.Response.Redirect("~/Login.aspx");
int sectionId = (int)HttpContext.Current.Session["section"];
string connectionString = GetEntityConnectionStringForSection(sectionId);
var context = new MyEntities(connectionString);
return context;
}
private static string GetEntityConnectionStringForSection(int section)
{
switch (section)
{
case 1: return ConfigurationManager.ConnectionStrings["entity_1"].ConnectionString;
case 2: return ConfigurationManager.ConnectionStrings["entity_2"].ConnectionString;
case 3: return ConfigurationManager.ConnectionStrings["entity_3"].ConnectionString;
default: return ConfigurationManager.ConnectionStrings["entity_1"].ConnectionString;
}
}
}
Inject this interface to repositories or other data access classes.
public partial class Store
{
private IContextProvider contextProvider;
public Store(IContextProvider contextProvider)
{
this.contextProvider = contextProvider;
}
public List<Store> GetSpecialStores()
{
using (var context = contextProvider.GetEntityContext())
{
return context.Stores.Where(qq => qq.Type > 0).OrderBy(qq => qq.Code).ToList();
}
}
}
here is i am trying to work.
List<MasterEmployee > masterEmployee = new List<MasterEmployee >();
masterEmployee = MasterEmployee.GetAll("123"); //connecting db and returning a list...
foreach (MasterEmployee item in masterEmployee)
{
foreach (Registration reg in item.Registration) //<<<error here...
{
//
}
}
error here:
Error 2 foreach statement cannot operate on variables of type Registration because Registration does not contain a public definition for 'GetEnumerator'
i have a class called MasterEmployee and in it i have a with few props and few methods on it
[Serializable]
public class MasterEmployee
{
//few props omitted ....
protected Registration _registration;
[CopyConstructorIgnore]
public Registration Registration
{
get
{
return _registration;
}
set
{
this._registration = value;
}
}
protected User _user;
[CopyConstructorIgnore]
public User MyUser
{
get
{
return _user;
}
set
{
this._user= value;
}
}
protected Student _student;
[CopyConstructorIgnore]
public Student Student
{
get
{
return _student;
}
set
{
this._student = value;
}
}
}
The explanation provided in the error message is clear enough. You are trying to iterate item.Registration, which is an instance of Registration. However, Registration is not derived from an iterable type, and does not implement the GetEnumerator function required for custom iterable types. So it cannot be iterated using a foreach loop.
But I believe either your naming conventions are incorrect, or you have misunderstood your data model. Why would a Registration instance ever contain a collection of Registration instances? If an item can have multiple Registration instances associated with it, then the property should be called something like item.Registrations, and it should not be of type Registration, it should be a list/collection type that contains Registration instances.
The class should be derived from IEnumerable.
reference and examples: http://msdn.microsoft.com/de-de/library/system.collections.ienumerable%28VS.80%29.aspx
I am working on a simple cart application that needs the ability to pass quantities for specific products in the URL. I imagined doing this by having a map property on a command object to keep the data binding simple. However, when I hit my action with a parameter that I would expect to be put into the map, I get the following error:
ERROR errors.GrailsExceptionResolver - Exception occurred when processing request: [GET] /mygrailsapp/action
itemQty[123].id: 5
java.lang.NullPointerException
at grails.plugin.springcache.web.GrailsFragmentCachingFilter.doFilter(GrailsFragmentCachingFilter.groovy:66)
at net.sf.ehcache.constructs.web.filter.Filter.doFilter(Filter.java:86)
at com.infusionsoft.cam.security.filter.BlackListIpAddressFilter.doFilter(BlackListIpAddressFilter.java:78)
at java.lang.Thread.run(Thread.java:662)
The command object looks like this:
class MyCommand {
Map itemQty
static constraints = {
itemQty(nullable: true, blank: true)
}
}
The controller action looks like this:
def action = {MyCommand myCommand ->
// some code
}
An example url I am hitting is /mygrailsapp/action?itemQty[123]=5
I am following the example from the Grails Docs for binding data to a map, the only difference is I am trying to do so from the URL and not from post like in the docs. I am using Grails 1.3.7. I have tried encoding the brackets - [ and ] - but I get the same error.
Any help would be appreciated. Thanks!
Edit: I found out that this is occurring because spring expects the map to have the key in it before setting the value and will not insert new entries.
I am now trying to use a custom binder to populate the map but the property editor class methods are never called.
Here is my property editor (I was calling super just to verify that control was getting to the method):
class ItemQuantityPropertyEditor extends PropertyEditorSupport {
#Override
public void setValue(Object value) {
super.setValue(value)
}
#Override
void setAsText(String text) {
super.setAsText(text)
}
#Override
Object getValue() {
return super.getValue()
}
#Override
String getAsText() {
return super.getAsText()
}
}
Here is the registrar:
class ItemQuantityPropertyEditorRegistrar implements PropertyEditorRegistrar {
void registerCustomEditors(PropertyEditorRegistry propertyEditorRegistry) {
propertyEditorRegistry.registerCustomEditor(MyCommand, "itemQty", new ItemQuantityPropertyEditor())
}
}
Here is my entry in resources.groovy:
beans = {
itemQuantityPropertyEditorRegistrar(ItemQuantityPropertyEditorRegistrar)
}
Try initialising the Map with a commons collections lazy map:
import org.apache.commons.collections.MapUtils
import org.apache.commons.collections.FactoryUtils
class MyCommand {
Map itemQty = MapUtils.lazyMap([:], FactoryUtils.constantFactory(''))
static constraints = {
itemQty(nullable: true, blank: true)
}
}
You should not need the custom binding PropertyEditor stuff...
How do I create a globally accessible Context object similar to the HttpContext object?
I want to create a custom class library which I want to reference from a website project. In the website project I want to be able to call the following globally:
ClassLibraryName.Context
I cannot create a global property directly in my classlibrary, so how should this be implemented? (I've seen other applications/products use this approach, one of which is Sitecore which has a custom Sitecore.Context object available)
Edit
Might this be a 'valid' solution?
namespace MyLibrary
{
public class Context
{
public static object ContextualObject
{
get;
set;
}
}
}
Yes, this is not hard to implement, if you always run this class in the context of an ASP.NET application, use this approach:
namespace MyLibrary
{
public class Context
{
public static object ContextualObject
{
get
{
var ctx = System.Web.HttpContext.Current.Items[typeof(Context)];
if (ctx == null)
{
ctx = new Context();
System.Web.HttpContext.Current.Items.Add(typeof(Context), ctx);
}
return ctx;
}
set { System.Web.HttpContext.Current.Items[typeof(Context)] = ctx; }
}
}
}
Essentially wrapping the existing HTTP context to provide your own service. This approach also doesn't store the object while the app lives, it only creates it for the current context, and when that response ends, it will die, and be regenerated during the next lifecycle. If that is not OK, store a static reference to context.
I've used this approach similarly in a class library I have at http://nucleo.codeplex.com, it works well.
HTH.
It depends on the lifetime you want the Context object to have. If you want all clients to use the same context, you can go with a singleton implementation.
If you want the context to be unique for each thread or http request you have to use a per request/thread implementation. One way to implement a per http request implementation would be to have a HttpModule create the object at every BeginRequest event and stick it in the HttpContext Items collection.
public static object ContextualObject
{
get { return HttpContext.Current.Items["MyContext"];}
}
You could create an instance of the object on Session_Start in the Global.asax.
I'm looking for a best practice solution that aims to reduce the amount of URLs that are hard-coded in an ASP.NET application.
For example, when viewing a product details screen, performing an edit on these details, and then submitting the changes, the user is redirected back to the product listing screen. Instead of coding the following:
Response.Redirect("~/products/list.aspx?category=books");
I would like to have a solution in place that allows me to do something like this:
Pages.GotoProductList("books");
where Pages is a member of the common base class.
I'm just spit-balling here, and would love to hear any other way in which anyone has managed their application redirects.
EDIT
I ended up creating the following solution: I already had a common base class, to which I added a Pages enum (thanks Mark), with each item having a System.ComponentModel.DescriptionAttribute attribute containing the page's URL:
public enum Pages
{
[Description("~/secure/default.aspx")]
Landing,
[Description("~/secure/modelling/default.aspx")]
ModellingHome,
[Description("~/secure/reports/default.aspx")]
ReportsHome,
[Description("~/error.aspx")]
Error
}
Then I created a few overloaded methods to handle different scenarios. I used reflection to get the URL of the page through it's Description attribute, and I pass query-string parameters as an anonymous type (also using reflection to add each property as a query-string parameter):
private string GetEnumDescription(Enum value)
{
Type type = value.GetType();
string name = Enum.GetName(type, value);
if (name != null)
{
FieldInfo field = type.GetField(name);
if (field != null)
{
DescriptionAttribute attr = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute)) as DescriptionAttribute;
if (attr != null)
return attr.Description;
}
}
return null;
}
protected string GetPageUrl(Enums.Pages target, object variables)
{
var sb = new StringBuilder();
sb.Append(UrlHelper.ResolveUrl(Helper.GetEnumDescription(target)));
if (variables != null)
{
sb.Append("?");
var properties = (variables.GetType()).GetProperties();
foreach (var property in properties)
sb.Append(string.Format("{0}={1}&", property.Name, property.GetValue(variables, null)));
}
return sb.ToString();
}
protected void GotoPage(Enums.Pages target, object variables, bool useTransfer)
{
if(useTransfer)
HttpContext.Current.Server.Transfer(GetPageUrl(target, variables));
else
HttpContext.Current.Response.Redirect(GetPageUrl(target, variables));
}
A typical call would then look like so:
GotoPage(Enums.Pages.Landing, new {id = 12, category = "books"});
Comments?
I'd suggest that you derive your own class ("MyPageClass") from the Page class and include this method there:
public class MyPageClass : Page
{
private const string productListPagePath = "~/products/list.aspx?category=";
protected void GotoProductList(string category)
{
Response.Redirect(productListPagePath + category);
}
}
Then, in your codebehind, make sure that your page derives from this class:
public partial class Default : MyPageClass
{
...
}
within that, you can redirect just by using:
GotoProductList("Books");
Now, this is a bit limited as is since you'll undoubtedly have a variety of other pages like the ProductList page. You could give each one of them its own method in your page class but this is kind of grody and not smoothly extensible.
I solve a problem kind of like this by keeping a db table with a page name/file name mapping in it (I'm calling external, dynamically added HTML files, not ASPX files so my needs are a bit different but I think the principles apply). Your call would then use either a string or, better yet, an enum to redirect:
protected void GoToPage(PageTypeEnum pgType, string category)
{
//Get the enum-to-page mapping from a table or a dictionary object stored in the Application space on startup
Response.Redirect(GetPageString(pgType) + category); // *something* like this
}
From your page your call would be: GoToPage(enumProductList, "Books");
The nice thing is that the call is to a function defined in an ancestor class (no need to pass around or create manager objects) and the path is pretty obvious (intellisense will limit your ranges if you use an enum).
Good luck!
You have a wealth of options availible, and they all start with creating a mapping dictionary, whereas you can reference a keyword to a hard URL. Whether you chose to store it in a configuration file or database lookup table, your options are endless.
You have a huge number of options available here. Database table or XML file are probably the most commonly used examples.
// Please note i have not included any error handling code.
public class RoutingHelper
{
private NameValueCollecton routes;
private void LoadRoutes()
{
//Get your routes from db or config file
routes = /* what ever your source is*/
}
public void RedirectToSection(string section)
{
if(routes == null) LoadRoutes();
Response.Redirect(routes[section]);
}
}
This is just sample code, and it can be implemented any way you wish. The main question you need to think about is where you want to store the mappings. A simple xml file could do it:
`<mappings>
<map name="Books" value="/products.aspx/section=books"/>
...
</mappings>`
and then just load that into your routes collection.
public class BasePage : Page
{
public virtual string GetVirtualUrl()
{
throw new NotImplementedException();
}
public void PageRedirect<T>() where T : BasePage, new()
{
T page = new T();
Response.Redirect(page.GetVirtualUrl());
}
}
public partial class SomePage1 : BasePage
{
protected void Page_Load()
{
// Redirect to SomePage2.aspx
PageRedirect<SomePage2>();
}
}
public partial class SomePage2 : BasePage
{
public override string GetVirtualUrl()
{
return "~/Folder/SomePage2.aspx";
}
}