Setting private set fields from a post request on backend server - c#

I am making my way through various todo list tutorials while learning react and entity framework. As some background I have made my way though Microsoft's todo list todo tutorial; although I have replaced the front end part of that with my own front end. It was all working fine, until I've tried to extend it and hit the issue I will outline below.
I have updated the EF model to include private set fields for the added benefits (becoming read only after it is initialised etc). This is shown in the code below.
public class TodoItem
{
public long id { get; private set; }
public string title { get; private set; }
public bool IsComplete { get; private set; }
// Define constructor
public TodoItem(long newId, string newTitle)
{
id = newId;
title = newTitle;
IsComplete = false;
}
public void ToggleComplete()
{
IsComplete = !IsComplete;
}
}
The post action from the controller is shown below. I have included some debug printouts as these show where the field is already showing the title as null.
I believe this is the section of code I am struggling with and would like to know what mistakes I am making or what the best practices are!
[HttpPost]
public async Task<ActionResult<TodoItem>> PostTodoItem(TodoItem item)
{
// returns null if model field set to private
System.Diagnostics.Debug.WriteLine("item title: " + item.title);
// Create new item passing in arguments for constructor
TodoItem newItem = new TodoItem(item.id, item.title);
_context.TodoItems.Add(newItem);
await _context.SaveChangesAsync();
return CreatedAtAction(nameof(GetTodoItem), new { id = newItem.id }, newItem);
}
The frontend method (js) where the post request is made is shown below:
const addTodoMethod = (title) => {
// Create new item
const item = {
title: title,
id: Date.now(),
isComplete: false,
}
// Update state
const newTodos = [...todos, item];
setTodos(newTodos);
// Can use POST requiest to add to db
axios.post('https://localhost:44371/api/todo/',
item)
.then(res=> {
console.log("Added item. Title: ", title);
})
.catch(function (error) {
console.log(error);
})}
I hope I've explained the problem well enough. Let me know if there is anything else needed!

I have updated the EF model to include private set fields for the added benefits (becoming read only after it is initialised etc).
There are two problems in what you did. The first one is that the Models must have a parameter-less constructor, and the second one that the properties must be public, both getter and setter.
The best you can do right now is to stop using your database entity for user input and create a ViewModel class:
public class TodoItemViewModel
{
public long id { get; set; }
public string title { get; set; }
public bool IsComplete { get; set; }
}
public async Task<ActionResult<TodoItem>> PostTodoItem(TodoItemViewModel model)
{
var item = new TodoItem(item.id, item.title);
...
}

Related

Upload file in angular / web API

I created a function that add a new user with Angular/WebAPI , so in angular i send the object like this :
AddUser(person : person):Observable<person>
{
return this.http.post<person>(this.baseUrl,person);
}
and in WebAPI i got the data :
[HttpPost]
public async Task<ActionResult<Person>> PostPerson(Person person)
{
Now I want to add a picture of each user, and i don't know how it's gonna be the objet in angular, should i add a property imageProfile as File which i'm not sure if it's possible , or it should be a string of the uploaded file.
export class person {
idPerson:number=0;
fname : string ="" ;
lname : string ="";
password : string ="";
idCategory? :number;
nameCategory:string="";
imageProfile :
}
That's very good info from Codemaze, as always. The remark from Lavstsen is not correct, there's no need for a separate call.
For example, you could have a form linked to the structure of the person-type:
initializeForm() {
this.personForm = this.form.group({
fname: [''],
})
}
In your onSubmit-method, you seize the date from your form and put in a dto, in this example through a getPersonDto-method
private getPersonDto(): PersonDto {
let dto = new PersonDto();
dto.fname = this.imageForm.controls.fname.value;
return dto;
}
and next you can solve it like this:
const formData = new FormData();
formData.append('Imagefile', this.selectedFile, this.selectedFile.name);
formData.append('fname', personDto.fname); // needs to be strings => toString()
this.personApiClient.uploadImageFile(this.personId, formData)
.subscribe((res: any) => {
this.uploadOrDeleteResults = res;
this.showToastrMessageSuccess("PAGES.COMMON.TOASTR.TITLE.SUCCESSFULCREATE", "PAGES.COMMON.TOASTR.MESSAGE.SUCCESSFULCREATE");
},
(error) => {
this.crudHasErrors = true;
this.errorHttpErrorResponse = error;
this.errors = this.errorHttpErrorResponse.error;
},
you don't need the dto-step as such, but if you structurally always use dto's in your application, it would make more sense
Take care and good luck
I have another workaround but this will only work for very small files where you don't need upload percentage to show on UI.
I have my controller like this:
[HttpPost("/api/sign-up")]
public void SaveUser([FromForm] UserModel info)
{
_logger.LogDebug(null, "Hello", info); // Just to see contents of info object in debugger
}
and make your model like this:
public class UserModel
{
[FromForm(Name = "avatar")]
public IFormFile Avatar { get; set; }
[FromForm(Name = "email")]
public string Email { get; set; }
}

C# - How to return an Array to set a Class property

I am trying to create a Class Method which can be called to Query the Database. The function itself works but for some reason, when the Array is returned, they're not set.
My function code is:
public Configuration[] tbl_bus(string type, string match)
{
// Create Obejct Instance
var db = new rkdb_07022016Entities2();
// Create List
List<Configuration> ConfigurationList = new List<Configuration>();
// Allow Query
if (type.ToLower() == "bustype")
{
foreach (var toCheck in db.tblbus_business.Where(b => b.BusType == match))
{
// Create Class Instance
var model = new Configuration { Name = toCheck.Name, BusinessID = toCheck.BusinessID };
// Append to the property
ConfigurationList.Add(model);
}
}
else if (type.ToLower() == "businessid")
{
foreach (var toCheck in db.tblbus_business.Where(b => b.BusinessID == match))
{
// Create Class Instance
var model = new Configuration { Name = toCheck.Name, BusinessID = toCheck.BusinessID };
// Append to the property
ConfigurationList.Add(model);
}
}
return ConfigurationList.ToArray();
}
And my Configuration code is:
public class Configuration
{
// Properties of the Database
public string Name { get; set; }
public string BusinessID { get; set; }
public string Address { get; set; }
}
public Configuration Config { get; set; }
public Controller()
{
this.Config = new Configuration();
}
On my Handler I am doing:
// Inside the NameSpace area
Controller ctrl;
// Inside the Main Void
ctrl = new Controller();
ctrl.tbl_bus("bustype", "CUS");
context.Response.Write(ctrl.Config.Name);
I tried watching the Class function and it does create the Array, only, when I watch the ctrl.Config.Name it is always set to NULL. Could anyone possibly help me in understanding why the return isn't actually setting the properties inside the Configuration class?
Edit: The function does run and it fetches 3006 rows of Data when matching the bus_type to customer. (Its a large Database) - Only, the properties are never set on return.
Edit: Is there a specific way to return an Array to a Class to set the Properties?
Thanks in advance!
Change your Configs in Controller to array
public Configuration[] Configs { get; set; }
Change your tbl_bus function to void, and set the Configs inside the function.
public void tbl_bus(string type, string match)
{
// do your code
// set the configs here
Configs = ConfigurationList.ToArray();
}
Hope it helps.
Although this is not a complete answer to your question, the problem probably lies in the fact that you're not doing anything with the array returned by the method. You're simply discarding it right away. If you change your code to
ctrl = new Controller();
Configuration[] config = ctrl.tbl_bus("bustype", "CUS");
you will be able to reference the array later on.
Console.WriteLine(config.Length);
Now you can use it to set any properties you like.

Selectively Whitelisting Model Fields to Bind

(I realize this question is very similar to How to whitelist/blacklist child object fields in the ModelBinder/UpdateModel method? but my situation is slightly different and there may be a better solution available now that wasn't then.)
Our company sells web-based software that is extremely configurable by the end-user. The nature of this flexibility means that we must do a number of things at run time that would normally be done at compile time.
There are some rather complex rules regarding who has read or read/write access to most everything.
For instance, take this model that we would like to create:
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Web;
using System.Web.Mvc;
namespace j6.Business.Site.Models
{
public class ModelBindModel
{
[Required]
[Whitelist(ReadAccess = true, WriteAccess = true)]
public string FirstName { get; set; }
[Whitelist(ReadAccess = true, WriteAccess = true)]
public string MiddleName { get; set; }
[Required]
[Whitelist(ReadAccess = true, WriteAccess = true)]
public string LastName { get; set; }
[Required]
[Whitelist(ReadAccess = User.CanReadSalary, WriteAccess = User.CanWriteSalary)]
public string Salary { get; set; }
[Required]
[Whitelist(ReadAccess = User.CanReadSsn, WriteAccess = User.CanWriteSsn)]
public string Ssn { get; set; }
[Required]
public string SirNotAppearingOnThisPage { get; set; }
}
}
In the controller, it is not difficult to "unbind" things manually.
var resetValue = null;
modelState.Remove(field);
pi = model.GetType().GetProperty(field);
if (pi == null)
{
throw new Exception("An exception occured in ModelHelper.RemoveUnwanted. Field " +
field +
" does not exist in the model " + model.GetType().FullName);
}
// Set the default value.
pi.SetValue(model, resetValue, null);
Using HTML helpers, I can easily access the model metadata and suppress rendering of any fields the user does not have access to.
The kicker: I can't figure out how to access the model metadata anywhere in the CONTROLLER itself to prevent over-posting.
Note that using [Bind(Include...)] is not a functional solution, at least not without additional support. The properties to Include are run-time (not compile time) dependent, and excluding the property does not remove it from the validation.
ViewData.Model is null
ViewData.ModelMetaData is null
[AllowAnonymous]
[HttpPost]
// [Bind(Exclude = "Dummy1" + ",Dummy2")]
public ViewResult Index(ModelBindModel dto)
{
zzz.ModelHelper.RemoveUnwanted(ModelState, dto, new string[] {"Salary", "Ssn"});
ViewBag.Method = "Post";
if (!ModelState.IsValid)
{
return View(dto);
}
return View(dto);
}
Any suggestions on how to access the Model MetaData from the controller? Or a better way to whitelist properties at run time?
Update:
I borrowed a page from this rather excellent resource:
http://www.dotnetcurry.com/ShowArticle.aspx?ID=687
With a model that looks like this:
[Required]
[WhiteList(ReadAccessRule = "Nope", WriteAccessRule = "Nope")]
public string FirstName { get; set; }
[Required]
[WhiteList(ReadAccessRule = "Database.CanRead.Key", WriteAccessRule = "Database.CanWrite.Key")]
public string LastName { get; set; }
The class:
public class WhiteList : Attribute
{
public string ReadAccessRule { get; set; }
public string WriteAccessRule { get; set; }
public Dictionary<string, object> OptionalAttributes()
{
var options = new Dictionary<string, object>();
var canRead = false;
if (ReadAccessRule != "")
{
options.Add("readaccessrule", ReadAccessRule);
}
if (WriteAccessRule != "")
{
options.Add("writeaccessrule", WriteAccessRule);
}
if (ReadAccessRule == "Database.CanRead.Key")
{
canRead = true;
}
options.Add("canread", canRead);
options.Add("always", "be there");
return options;
}
}
And adding these lines to the MetadataProvider class mentioned in the link:
var whiteListValues = attributes.OfType<WhiteList>().FirstOrDefault();
if (whiteListValues != null)
{
metadata.AdditionalValues.Add("WhiteList", whiteListValues.OptionalAttributes());
}
Finally, the heart of the system:
public static void DemandFieldAuthorization<T>(ModelStateDictionary modelState, T model)
{
var metaData = ModelMetadataProviders
.Current
.GetMetadataForType(null, model.GetType());
var props = model.GetType().GetProperties();
foreach (var p in metaData.Properties)
{
if (p.AdditionalValues.ContainsKey("WhiteList"))
{
var whiteListDictionary = (Dictionary<string, object>) p.AdditionalValues["WhiteList"];
var key = "canread";
if (whiteListDictionary.ContainsKey(key))
{
var value = (bool) whiteListDictionary[key];
if (!value)
{
RemoveUnwanted(modelState, model, p.PropertyName);
}
}
}
}
}
To recap my interpretation of your question:
Field access is dynamic; some users may be able to write to a field and some may not.
You have a solution to control this in the view.
You want to prevent a malicious form submission from sending restricted properties, which the model binder will then assign to your model.
Perhaps something like this?
// control general access to the method with attributes
[HttpPost, SomeOtherAttributes]
public ViewResult Edit( Foo model ){
// presumably, you must know the user to apply permissions?
DemandFieldAuthorization( model, user );
// if the prior call didn't throw, continue as usual
if (!ModelState.IsValid){
return View(dto);
}
return View(dto);
}
private void DemandFieldAuthorization<T>( T model, User user ){
// read the model's property metadata
// check the user's permissions
// check the actual POST message
// throw if unauthorized
}
I wrote an extension method a year or so ago that has stood me in good stead a couple of times since. I hope this is of some help, despite not being perhaps the full solution for you. It essentially only allows validation on the fields that have been present on the form sent to the controller:
internal static void ValidateOnlyIncomingFields(this ModelStateDictionary modelStateDictionary, FormCollection formCollection)
{
IEnumerable<string> keysWithNoIncomingValue = null;
IValueProvider valueProvider = null;
try
{
// Transform into a value provider for linq/iteration.
valueProvider = formCollection.ToValueProvider();
// Get all validation keys from the model that haven't just been on screen...
keysWithNoIncomingValue = modelStateDictionary.Keys.Where(keyString => !valueProvider.ContainsPrefix(keyString));
// ...and clear them.
foreach (string errorKey in keysWithNoIncomingValue)
modelStateDictionary[errorKey].Errors.Clear();
}
catch (Exception exception)
{
Functions.LogError(exception);
}
}
Usage:
ModelState.ValidateOnlyIncomingFields(formCollection);
And you'll need a FormCollection parameter on your ActionResult declaration, of course:
public ActionResult MyAction (FormCollection formCollection) {

Trying to pass a parameter but getting a "context" error

I am trying to pass this from my controller into my view (#ViewBag.Chapter7Total):
ViewBag.Chapter7Total = calc.CalculatePrice(quoteData, Chapter7);
But am getting a "doesn't exist in the current context error" in VS.
Basically, I am trying to pass in a second parameter which determines which pricing structure to use between 2. Chapter7 or Chapter13, with the selection determining the second parameter to perform calculations with.
Here are my methods:
class Chapter
{
public decimal PaymentPlan { get; set; }
public decimal Price { get; set; }
}
public decimal decPaymentPlan(QuoteData quoteData, Chapter chapter)
{
if (quoteData.StepFilingInformation.PaymentPlanRadioButton
== StepFilingInformation.PaymentPlan.No)
return PriceQuote.priceNoPaymentPlan;
else
return chapter.PaymentPlan;
}
public decimal Calculate(QuoteData quoteData, Chapter chapter)
{
decimal total = chapter.Price;
total += this.decPaymentPlan(quoteData, chapter);
return total;
}
static Chapter Chapter7 = new Chapter() { Price = 799.00m, PaymentPlan = 100.00m };
Finally, this is my controller:
public ActionResult EMailQuote()
{
Calculations calc = new Calculations();
Chapter chap = new Chapter();
QuoteData quoteData = new QuoteData
{
StepFilingInformation = new Models.StepFilingInformation
{
//just moking user input here temporarily to test out the UI
PaymentPlanRadioButton = Models.StepFilingInformation.PaymentPlan.Yes,
}
};
var total = calc.CalculatePrice(quoteData);
ViewBag.Chapter7Total = calc.CalculatePrice(quoteData, Chapter7);
return View(quoteData);
}
I'm not sure what to do to pass Chapter7. Any thoughts?
UPDATE 1:
This is my ViewModel (QuoteData):
public class QuoteData
{
public PriceQuote priceQuote;
public Calculations calculations;
public StepFilingInformation stepFilingInformation { get; set; }
public QuoteData()
{
PriceQuote = new PriceQuote();
Calculations = new Calculations();
}
}
I'm trying to figure out what you are doing here but I see that most importantly, you are sending quoteData to your View. I'm making a guess here but I figure QuoteData is a custom entity type of yours and not a ViewModel.
To start, I would create a QuoteDataViewModel in your models with all the properties of QuoteData that you need, including
public class QuoteDataViewModel {
... all of your quoteData properties here
public Chapter Chapter7 { get; set; }
}
In your EMailQuote action, something similar to this
public ActionResult EMailQuote() {
...
var model = new QuoteDataViewModel();
var quoteData = new QuoteData();
... // map your quoteData to your model with Automapper or manually like
... // model.SomeProperty = quoteData.SomeProperty;
... // repeat for all properties
model.Chapter7 = Chapter7;
return View(model);
}
If you are posting this data back you would need your Post action to accept the new QuoteDataViewModel
public ActionResult EmailQuote(QuoteDataViewModel model) {
if(ModelState.IsValid) {
....//save data that was entered?
}
return View(model);
}
Your view would then take a QuoteDateViewModel
#model QuoteDataViewModel
This is all just how I would do it personally, I don't quite understand what you have going on, for example, this line:
var total = calc.CalculatePrice(quoteData);
I don't see total ever being used after you create it.
Anyway, that's just a sample of how I'd do it, create a model specific to the view, include any and all properties I need, populate the model in the controller and send it to the view
Update
Based on the OP comment that quoteData is a ViewModel, then just as above, adding the new property to hold the extra data is simple, by adding ...
public decimal QuoteTotal { get; set; }
public Chapter Chapter7 { get; set; }
...to the ViewModel
the controller populates
var total = calc.CalculatePrice(quoteData);
model.QuoteTotal = total;
model.Chapter7 = new Chapter();
model.Chapter7 = Chapter7;
In the View the values can be accessed like:
#Html.DisplayFor(model => model.QuoteTotal)
#Html.DisplayFor(model => model.Chapter7.PaymentPlan)
#Html.DisplayFor(model => model.Chapter7.Price)

ASP.NET MVC TryValidateModel() Issues when Model is Modified

I have a two step form process where the first set of data is stored in session.
[IsMp4File]
[Required(ErrorMessage = "* Please select a video to upload")]
public HttpPostedFileBase VideoClip { get; set; }
[Required(ErrorMessage = "* Please select a thumbmail image")]
public HttpPostedFileBase VideoThumbnail{ get; set; }
public string VideoFileName { get { return VideoClip.FileName; } }
public NewsWizardStep CurrentStep { get; set; }
...
public enum NewsWizardStep : int
{
One = 1,
Two = 2,
Three = 3,
Four = 4,
Five = 5,
Six = 6
}
Controller
public ActionResult TvCreate(TvNewsVideoVM modelVM)
{
if (modelVM.CurrentStep == NewsWizardStep.Two)
{
var sessionModel = ((TvNewsVideoVM)Session["TvModelVM"]);
modelVM.VideoClip = sessionModel.VideoClip;
modelVM.VideoThumbnail = sessionModel.VideoThumbnail;
}
if (TryValidateModel(modelVM))
{
...
}
}
TryValidateModel(modelVM) returns false, saying VideoClip and VideoThumnail are required, despite mapping them from the seesionModel to the viewModel. I have added a breakpoint and checked they are not null.
It looks like there is some underlying functionality I am not aware of regarding how ModelState and ValidateModel() work , I just don't know what.
UPDATE
I wouldn't say I have resolved the issue but figured out a workaround that isn't that pretty, By going into the ModelState it is possible to set the ModelValue using SetModelValue() then manually remove the error from the model state and then call TryValidateModel() - you might not even have to add the values just remove the error I have not tried. Here is my work around.
if (modelVM.CurrentStep == NewsWizardStep.Two)
{
var sessionModel = ((MtTvNewsVideoVM)Session["MtTvModelVM"]);
modelVM.VideoClip = sessionModel.VideoClip;
modelVM.VideoThumbnail = sessionModel.VideoThumbnail;
ModelState.SetModelValue("VideoClip", new ValueProviderResult(sessionModel.VideoThumbnail, sessionModel.VideoFileName, CultureInfo.CurrentCulture));
ModelState.SetModelValue("VideoThumbnail", new ValueProviderResult(sessionModel.VideoClip, sessionModel.VideoFileName, CultureInfo.CurrentCulture));
ModelState["VideoClip"].Errors.RemoveAt(0);
ModelState["VideoThumbnail"].Errors.RemoveAt(0);
}
During the model binding the DefaultModelBinder validates your action parameters.
So when the execution hits your public ActionResult TvCreate(TvNewsVideoVM modelVM) method
the ModelState is already containing the validation errors.
When you call TryValidateModel it doesn't clear the ModelState so the validation errors remain there that is why it returns false. So you need to clear the ModelState collection if you want to redo the validation later manually:
public ActionResult TvCreate(TvNewsVideoVM modelVM)
{
ModelState.Clear();
if (modelVM.CurrentStep == NewsWizardStep.Two)
{
var sessionModel = ((TvNewsVideoVM)Session["TvModelVM"]);
modelVM.VideoClip = sessionModel.VideoClip;
modelVM.VideoThumbnail = sessionModel.VideoThumbnail;
}
if (TryValidateModel(modelVM))
{
...
}
}

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