I want to retrieve the http method of the spring's <form:form> tag from inside a RequestDataValueProcessor in order to generate different hidden fields depending on it. I have access to the form action, but it seems there is no way to retrieve the http method of the form.
I am using Spring 3.2.
Edit: I have added an example.
Imagine the form below being retrieved with GET. What I want is to read the method parameter of the <form:form> tag in order to add a hidden field depending on the method. Obviously, I can't use request.getMethod() because this would return the method of the original request, not the method of the form being processed by RequestDataValueProcessor.
<form:form action="/foo/bar" method="post" modelAttribute="${modelAttribute}" >
<form:input path="myField" />
<input id="proceed" type="submit" value="Save" />
</form:form>
It seems that there is a pending issue to allow access to the form method in RequestDataValueProcessor.
This is the issue: https://jira.springsource.org/browse/SPR-10041
Definitely an open issue on Spring, but doesn't look like its going to be addressed soon.
Here is what you can do.. its not straight forward though, so weigh the cost vs benefit before you start :)
RequestDataValueProcessor will not work for you, you already know that. The way the FormTag is programmed, it calls specific methods (hooks) from the value processor at specific times, during the execution of the form tag.
You can create your own custom form tag, which will do everything Spring's form tag does, either by composition or inheritence. But in addition, you can call your own Value Processor esque class when the form method is detected by the tag. This class can then decide what additional steps you want to take and you can then use the regular ValueProcessor to add hidden fields as you see fit.
These questions talk about how to extend spring's tags, by creating your own: SpringMVC Custom Form Tags and Create a custom tag library which extends the Spring tag library.
Also look at the source code of the FormTag https://github.com/SpringSource/spring-framework/blob/master/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/form/FormTag.java. See how the protected processAction method calls the value processor hook, you'll have to do something similar, but in the getMethod method.
Hope this answer makes sense, let me know if you want me to re-phrase or elaborate any point.
Happy programming!
A little more information would be helpful such as what version of Spring you are using.
From the Spring 3.2 API Documentation for RequestDataValueProcessor, I see that there are four (4) methods that you could possibly be working within. In each of those, you have access to the HttpServletRequest.
Accordingly, you have access to whatever HTTP Method the inbound request was made with by calling (link):
request.getMethod()
This should give you exactly what you're looking for.
Related
I have a use case where I used different models for the GET and POST actions in my controller. This works great for my view, because most of the data goes into labels. The model for the GET method contains 10 properties, but the model for the POST method only needs 3.
This GET view renders a form, which only needs 3 of these properties, not all 10. Thus, the model for the POST method accepts a model class which contains only these 3 properties. Therefore, the ASP.Net MVC model binder populates the model class parameter on my POST method with only these 3 necessary properties, and all is well.
Here's the question: When I encounter some business rule violation in the POST method, and want to use ModelState.AddModelError, and re-display the original view, I no longer have the 7 properties that were not POSTed, as they were not part of the form, and are not part of the model class which this method takes as its parameter.
Currently, I'm calling into a builder to return an instance of the model class for the POST method, and have the GET method itself delegating to the same builder. So, in these cases, when there is some business rule violation in the POST method, I return a View("OriginalGetView", originalGetModel). How can I use ModelState.AddModelError in this case, in the POST method, if I want to send custom messages back to the view, using a completely different model class?
It seemed way too lazy to use the same model class for both the GET and POST methods, given that their needs were so different. What is the best practice here? I see a lot of people recommending to use the same model for both methods, and to POST all of the fields back from hidden form fields, but that just seems like a waste of bandwidth in the majority of cases, and it feels ugly to be sending things like "VendorName" back to the server, when I already have "VendorId".
I may be misunderstanding what you are trying to do, but make sure you aren't being penny-wise and pound foolish. I see you may only want to post the identifiers and not necessarily the descriptors. But it sounds like you have to re-display the view after posting...if so you can just access the model properties if you post the same model that is in the get. If you only post the identifiers, you have to spend time re-accessing the database to get the description values(i.e. vendorname as you describe) using the vendor id no? Wouldn't that also be extra processing? Like I said, I could be misunderstanding your post, but for consistency using the same view model for your view to get and post makes the most sense to me.
Hidden Inputs maybe the best solution here still I think, even on 2g you shouldn't create any lag unless unless the values of your Model properties are long strings or something encrypted or xml.
So your .cshtml would have this in it for the 4 properties not currently included in the form:
<form>
#Html.HiddenFor(m => m.Property1)
#Html.HiddenFor(m => m.Property2)
#Html.HiddenFor(m => m.Property3)
#Html.HiddenFor(m => m.Property4)
But you could also get the model state errors from the original posted model and recreate the ModelError state in your response model to get around using hidden inputs.
I just found this guide (not the answer with Green Checkmark but the highest upped Answer: ASP.NET MVC - How to Preserve ModelState Errors Across RedirectToAction?
Note: if you need to copy model properties from Model to another Model (of the same type or different type), in a cleaner way, check out AutoMapper.
Perhaps this could help with what you were trying to achieve - 'Model' level errors - which wouldn't need to attach to a specific field/property - but can be displayed in a Global area.
https://stackoverflow.com/a/53716648/10257093
Is there an API for adding to the Form Results that results from standard Forms are added to from an External Form?
I want to try avoid adding to the tables btform, btformanswers, etc. manually
No.
See https://github.com/concrete5/concrete5/blob/master/web/concrete/core/controllers/blocks/form.php#L354-L415 -- the core's form block updates the table manually.
As johjoh says, you could theoretically mimic a post to a form block, by instantiating it and then calling action_submit_form(), but that's just as fraught with difficulty, too... you'd have to keep the "form" in sync with your data, and possibly worry about the token and block ID and all that....
What's your exact use case? New block type? Some sort of external API? The form viewing interface in the dashboard is nice, but nothing that special. I think most people want to get data out of it, not in....
I am kind of new to spring MVC
and I wanted to use JasonViews (Jackson) for dynamic JSON per request and I didn't want to change my controllers too much .. so #marty here gave me a great solution in his blog
http://martypitt.wordpress.com/2012/11/05/custom-json-views-with-spring-mvc-and-jackson/
The problem is that I need control over the HTTP status codes,so my controllers are returning types of HttpResponse{T} and not List{T} how can I customize the code in order to support parsing of types like HttpResponse{List{Book}}?
If not possible, can I control the Http status code without the HttpResponse?
I may need to see an example of your code to really understand what you are asking, but this might point you in the right direction:
Take #marty's code and try extending HttpEntityMethodProcessor with it.
http://static.springsource.org/spring/docs/3.1.x/javadoc-api/org/springframework/web/servlet/mvc/method/annotation/HttpEntityMethodProcessor.htmlS
Then, you need to make your method signatures look like
public ResponseEntity<MyType> getMyTypeWithControlOverResponseEntity(...) {...}
You can find more info on this signature type at:
http://static.springsource.org/spring/docs/current/spring-framework-reference/htmlsingle/#mvc-ann-httpentity
Let me know if this is not the right direction you were trying to go or need more help. =)
I need to get some Json to the client side from the server and it's somewhat troublesome as almost all tutorials assume an Ajax call to a separate action to get the Json.
This led me to think that there must be some reason why it is done this way. In Asp.Net MVC we can pass a Model along with the view to get the information but we can't seem to easily pass a Json object. Instead you are supposed to make a separate call to get this information.
What if the Json info is known when the page is generated, why not generate it at the same time?
I'm sorry if I wasn't clear enough. While it's nice to hear of ways to get Json to the client, the question is actually whether there is a specific reason the Ajax call method is much more popular, like security or anything like that.
Can you put something like this into your view? (rough pseudo code, assuming using a Razor view)
< script >
var myJSON = { Field: #model.Field, Field2: #model.Field2 };
< /script >
Because you do not need both at the same time... on the first call will be to get html (the view of the data - represented by a view model), and any ajax calls will be to get the possibly updated data (json serialized view model).
No reason why you can't. You could use the javacript serializer to create a JSON string that drop on the page. You could also create an action that return the json string that you called from a script tag.
What you want if you're using KnockOut, would be the Mapping plugin that turns an ordinary JS object, like that generated above, into an observable ready for KnockOut to use. See here from info. http://knockoutjs.com/documentation/plugins-mapping.html
You can use content-negotiation by setting accept header. This is considered a best practice (and according to some RESTful).
This needs to be supported and implemented at server as well. ASP NET MVC does not make it easy to support content-negotiation and you have to implement it yourself by if-else or using ActionFilter and implementing action selector.
I am building a site in which we are making moderate use of email templates. As in, HTML templates which we pass tokens into like {UserName}, {Email}, {NameFirst}, etc.
I am struggling with where to store these, as far as best practice goes. I'll first show the approach I took, and I'd be really excited to hear some expert perspective as a far as alternate approaches.
I created HTML templates in a folder called /Templates/.
I call a static method in my service layer, which takes in the following arguments:
UserName
UserID
Email
TemplatePath ("~/Templates")
Email Subject
Within the service layer I have my static method SendUserEmail() which makes use of a Template class - which takes a path, loads it as a string, and has a AddToken() Method.
Within my static SendUserEmail(), I build the token list off of the method signature, and send the email.
This makes for a quite long method call in my actual usage, especially since I am calling from the web.config the "TemplatePath", and "Email Subject". I could create a utility that has a shorter method call than the ConfigurationManager.AppSettings, but my concern is more that I don't usually see method signatures this long and I feel like it's because I'm doing something wrong.
This technique works great for the emails I have now, which at the most are using the first 3 tokens. However in the future I will have more tokens to pass in, and I'm just wondering what approach to take.
Do I create methods specific to the email needing to be sent? ie. SendNewUserRegistration(), SendMarketingMaterial(), and each has a different signature for the parameters?
I am using ASP.NET Membership, which contains probably the extend of all the fields I'll ever need. There are three main objects, aspnet_User, aspnet_Mebership and aspnet_profile. If it was all contained in one object, I would have just passed that in. Is there performance concerns with passing in all 3, to get all the fields I need? That is versus just passing in aspnet_User.UserID, aspnet_User.Email, etc?
I could see passing in a dictionary with the token entries, but I'm just wondering if that is too much to ask the calling page?
Is there a way to stick these in a config file of it's own called Templates.config, which has tags like -
<Templates>
<EmailTemplate Name="New User Registration">
<Tokens>
<UserName>
<UserID>
<Email>
</Tokens>
<Message Subject="Hi welcome...">
Hi {UserName}...
</Message>
</EmailTemplate>
</Templates>
I guess the main reason I'm asking, is because I'm having a hard time determining where the responsibility should be as far as determining what template to use, and how to pass in parameters. Is it OK if the calling page has to build the dictionary of TokenName, TokenValue? Or should the method take each in as a defined parameter? This looks out of place in the web.config, because I have 2 entries for and , and it feels like it should look more nested.
Thank you. Any techniques or suggestions of an objective approach I can use to ask whether my approach is OK.
First of all I would like to suggest you to use NVelocity as a template engine. As for main problem I think you can create an abstract class MailMessage and derive each one for every needed message (with unique template). So you will use this like following:
MailMessage message = new UserRegistrationMessage(tokens);
//some code that sends this message
Going this way you force each concrete XXXMessage class to be responsible for storing a template and filling it with the given tokens. How to deal with tokens? The simpliest way is to create a dictionary before passing it to the message, so each concrete message class will know how to deal with passed dictionary and what tokens it should contain, but you also need to remember what tokens it should contain. Another way (I like it more) is to create a general abstract type TokenSet and a derived one for every needed unique set of tokens. For example you can create a UserMessageTokenSet : TokenSet and several properties in it:
UserNameToken
SomeUserProfileDataToken
etc. So using this way you will always know, what data you should set for each token set and
UserRegistrationMessage will know what to take from this tokenSet.
There are a lot of ways to go. If you will describe you task better I think I will try suggest you something more concrete. But general idea is listed above. Hope it helps =)