I get a Stack Overflow error but I don't seem to know what's wrong. This is Database class helps me to get FirebaseDatabase information.
import 'package:firebase_database/firebase_database.dart';
import 'User.dart';
import 'dart:async';
class FireDatabase{
FireDatabase();
DatabaseReference userRef = FirebaseDatabase.instance.reference().child("users");
DatabaseReference transactionsRef = FirebaseDatabase.instance.reference().child("transactions");
User user = new User();
getDatabaseUser(String cUid){
userRef.orderByChild(cUid).once().then((DataSnapshot data){
if (data.value!=null) {
return data.value;
} else {
print("prints - database.dart : data.value of user is empty/null");
return null;
}
},onError: (e){
print("prints - database.dart " + e.toString());
return null;
});
return null;
}
getDatabaseTransactions(String cUid) {
transactionsRef.orderByChild("transactions").once().then((DataSnapshot data){
if(data.value!=null) {
return data.value;
} else {
print("prints - database.dart : data.value of user is empty/null");
return null;
}
},onError: (e){
print("prints - database.dart " + e.toString());
return null;
});
return null;
}
getDatabaseTransaction(String cUid) {
transactionsRef.orderByChild(cUid).limitToFirst(1).once().then((DataSnapshot data){
if(data.value!=null) {
return data.value;
} else {
print("prints - database.dart : data.value of user is empty/null");
return null;
}
},onError: (e){
print("prints - database.dart " + e.toString());
return null;
});
return null;
}
}
For me, the problem was that I had 2 classes, now within both classes, I instantiated each other class.
Here is an example:
class Firestore{
final auth = Auth();
}
class Auth{
final fireStore = Firestore();
}
As you can see each class is calling the other class, that what caused the StackOverflow.
Instantiating a User class in the Database class
User user = new User();
seem to have been the problem but luckily I was not using it anyway, the User gets stored in the User class
Related
I don't know why the _userFromFirebaseUser function will not let me return null. Not only that but I'm getting an error when I pass _userFromFirebaseUser to the map() function?
final FirebaseAuth _auth = FirebaseAuth.instance;
//user object based on FirebaseUser
Users _userFromFirebaseUser(User user){
if (user != null){
return Users(uid: user.uid);
}
return null;
}
//auth change user stream
Stream<Users> get user {
return _auth.authStateChanges().map(_userFromFirebaseUser);
}
Make return type nullable by adding "?"
Users? _userFromFirebaseUser(User user){
if (user != null){
return Users(uid: user.uid);
}
return null;
}
Stream<Users?> get user {
return _auth.authStateChanges().map(_userFromFirebaseUser);
}
My cache class
import 'dart:async';
import 'dart:convert';
import 'package:shared_preferences/shared_preferences.dart';
class CacheUtil{
static set(String key, value) async{
if(value is Map || value is List){
value = json.encode(value);
}
SharedPreferences preferences = await SharedPreferences.getInstance();
preferences.setString(key, json.encode(value));
}
static get(String key) async{
SharedPreferences preferences = await SharedPreferences.getInstance();
String data = preferences.getString(key);
return data;
}
}
In the get method ,I want to see if value can be json.decode
what should I do?
Just try to decode it and catch FormatException to know when it failed:
void main() {
var jsonString = '{"abc';
var decodeSucceeded = false;
try {
var decodedJSON = json.decode(jsonString) as Map<String, dynamic>;
decodeSucceeded = true;
} on FormatException catch (e) {
print('The provided string is not valid JSON');
}
print('Decoding succeeded: $decodeSucceeded');
}
I like something that looks like int.tryParse(data).
So I using this.
import 'dart:convert';
class Json {
static String? tryEncode(data) {
try {
return jsonEncode(data);
} catch (e) {
return null;
}
}
static dynamic tryDecode(data) {
try {
return jsonDecode(data);
} catch (e) {
return null;
}
}
}
Using like this.
void main() {
String? jsonEncode = Json.tryEncode(dataEncoded);
if (jsonEncode == null) {
print("jsonEncode is null");
} else {
print("jsonEncode is not null");
}
dynamic jsonDecode = Json.tryDecode(dataDecoded);
if (jsonDecode == null) {
print("jsonDecode is null");
} else {
print("jsonDecode is not null");
}
}
Caution: When you use Json.tryDecode( jsonEncode(null) ) that function can't tell you if this can convert to JSON or not because the result always is null. But I don't worry about this.
I've set a custom unique validator decorator on my TypeORM entity field email. NestJS has dependency injection, but the service is not injected.
The error is:
TypeError: Cannot read property 'findByEmail' of undefined
Any help on implementing a custom email validator?
user.entity.ts:
#Column()
#Validate(CustomEmail, {
message: "Title is too short or long!"
})
#IsEmail()
email: string;
My CustomEmail validator is
import {ValidatorConstraint, ValidatorConstraintInterface,
ValidationArguments} from "class-validator";
import {UserService} from "./user.service";
#ValidatorConstraint({ name: "customText", async: true })
export class CustomEmail implements ValidatorConstraintInterface {
constructor(private userService: UserService) {}
async validate(text: string, args: ValidationArguments) {
const user = await this.userService.findByEmail(text);
return !user;
}
defaultMessage(args: ValidationArguments) {
return "Text ($value) is too short or too long!";
}
}
I know I could set unique in the Column options
#Column({
unique: true
})
but this throws a mysql error and the ExceptionsHandler that crashes my app, so I can't handle it myself...
Thankx!
I can propose 2 different approaches here, the first one catches the constraint violation error locally without additional request, and the second one uses a global error filter, catching such errors in the entire application. I personally use the latter.
Local no-db request solution
No need to make additional database request. You can catch the error violating the unique constraint and throw any HttpException you want to the client. In users.service.ts:
public create(newUser: Partial<UserEntity>): Promise<UserEntity> {
return this.usersRepository.save(newUser).catch((e) => {
if (/(email)[\s\S]+(already exists)/.test(e.detail)) {
throw new BadRequestException(
'Account with this email already exists.',
);
}
return e;
});
}
Which will return:
Global error filter solution
Or even create a global QueryErrorFilter:
#Catch(QueryFailedError)
export class QueryErrorFilter extends BaseExceptionFilter {
public catch(exception: any, host: ArgumentsHost): any {
const detail = exception.detail;
if (typeof detail === 'string' && detail.includes('already exists')) {
const messageStart = exception.table.split('_').join(' ') + ' with';
throw new BadRequestException(
exception.detail.replace('Key', messageStart),
);
}
return super.catch(exception, host);
}
}
Then in main.ts:
async function bootstrap() {
const app = await NestFactory.create(/**/);
/* ... */
const { httpAdapter } = app.get(HttpAdapterHost);
app.useGlobalFilters(new QueryErrorFilter(httpAdapter));
/* ... */
await app.listen(3000);
}
bootstrap();
This will give generic $table entity with ($field)=($value) already exists. error message. Example:
I have modified my code. I am checking the uniqueness of username/email in the user service (instead of a custom validator) and return an HttpExcetion in case the user is already inserted in the DB.
The easiest solution!
#Entity()
export class MyEntity extends BaseEntity{
#Column({unique:true}) name:string;
}
export abstract class BaseDataService<T> {
constructor(protected readonly repo: Repository<T>) {}
private async isUnique(t: any) {
const uniqueColumns = this.repo.metadata.uniques.map(
(e) => e.givenColumnNames[0]
);
for (const u of uniqueColumns) {
const count = await this.repo.count({ where: { [u]: ILike(t[u]) } });
if (count > 0) {
throw new UnprocessableEntityException(`${u} must be unique!`);
}
}
}
async save(body: DeepPartial<T>) {
await this.isUnique(body);
try {
return await this.repo.save(body);
} catch (err) {
throw new UnprocessableEntityException(err.message);
}
}
async update(id: number, updated: QueryDeepPartialEntity<T>) {
await this.isUnique(updated)
try {
return await this.repo.update(id, updated);
} catch (err) {
throw new UnprocessableEntityException(err.message);
}
}
}
An approach that works for modern version of NestJS which is based in Daniel Kucal's answer and actually returns the error to the frontend when calling the JSON API is the following:
import {
Catch,
ArgumentsHost,
BadRequestException,
HttpException,
} from '#nestjs/common';
import { BaseExceptionFilter } from '#nestjs/core';
import { QueryFailedError } from 'typeorm';
type ExceptionType = { detail: string; table: string };
#Catch(QueryFailedError)
export class QueryErrorFilter extends BaseExceptionFilter<
HttpException | ExceptionType
> {
public catch(exception: ExceptionType, host: ArgumentsHost): void {
const { detail = null } = exception || {};
if (
!detail ||
typeof detail !== 'string' ||
// deepcode ignore AttrAccessOnNull: <False positive>
!detail.includes('already exists')
) {
return super.catch(exception, host);
} // else
/**
* this regex transform the message `(phone)=(123)` to a more intuitive `with phone: "123"` one,
* the regex is long to prevent mistakes if the value itself is ()=(), for example, (phone)=(()=())
*/
const extractMessageRegex =
/\((.*?)(?:(?:\)=\()(?!.*(\))(?!.*\))=\()(.*?)\)(?!.*\)))(?!.*(?:\)=\()(?!.*\)=\()((.*?)\))(?!.*\)))/;
const messageStart = `${exception.table.split('_').join(' ')} with`;
/** prevent Regex DoS, doesn't treat messages longer than 200 characters */
const exceptionDetail =
exception.detail.length <= 200
? exception.detail.replace(extractMessageRegex, 'with $1: "$3"')
: exception.detail;
super.catch(
new BadRequestException(exceptionDetail.replace('Key', messageStart)),
host,
);
}
}
Also, not forgetting main.ts:
async function bootstrap() {
const app = await NestFactory.create(/**/);
/* ... */
const { httpAdapter } = app.get(HttpAdapterHost);
app.useGlobalFilters(new QueryErrorFilter(httpAdapter));
/* ... */
await app.listen(3000);
}
bootstrap();
How can I display ModelState errors returned by JSON?
I want to do something like this:
if (!ValidateLogOn(Name, currentPassword))
{
ModelState.AddModelError("_FORM", "Username or password is incorrect.");
//Return a json object to the javascript
return Json(new { ModelState });
}
What must be my code in the view to read the ModelState errors and display them?
My actual code in the view to read the JSON values is as follows:
function createCategoryComplete(e) {
var obj = e.get_object();
alert(obj.Values);
}
This is draft code but the same idea works for me in production.
The main idea here is that Json errors have predefined tag names, that no normal objects will have. For errors validation errors HTML is re-created using JavaScript (both top summary and form elements highlighting).
Server side:
public static JsonResult JsonValidation(this ModelStateDictionary state)
{
return new JsonResult
{
Data = new
{
Tag = "ValidationError",
State = from e in state
where e.Value.Errors.Count > 0
select new
{
Name = e.Key,
Errors = e.Value.Errors.Select(x => x.ErrorMessage)
.Concat(e.Value.Errors.Where(x => x.Exception != null).Select(x => x.Exception.Message))
}
}
};
}
in action:
if (!ModelState.IsValid && Request.IsAjaxRequest())
return ModelState.JsonValidation();
Client side:
function getValidationSummary() {
var el = $(".validation-summary-errors");
if (el.length == 0) {
$(".title-separator").after("<div><ul class='validation-summary-errors ui-state-error'></ul></div>");
el = $(".validation-summary-errors");
}
return el;
}
function getResponseValidationObject(response) {
if (response && response.Tag && response.Tag == "ValidationError")
return response;
return null;
}
function CheckValidationErrorResponse(response, form, summaryElement) {
var data = getResponseValidationObject(response);
if (!data) return;
var list = summaryElement || getValidationSummary();
list.html('');
$.each(data.State, function(i, item) {
list.append("<li>" + item.Errors.join("</li><li>") + "</li>");
if (form && item.Name.length > 0)
$(form).find("*[name='" + item.Name + "']").addClass("ui-state-error");
});
}
$.ajax(... function(response) {
CheckValidationErrorResponse(xhr.responseText); } );
Why not return the original ModelState object to the client, and then use jQuery to read the values. To me it looks much simpler, and uses the common data structure (.net's ModelState)
C#:
return Json(ModelState);
js:
var message = "";
if (e.response.length > 0) {
$.each(e.response, function(i, fieldItem) {
$.each(fieldItem.Value.Errors, function(j, errItem) {
message += errItem.ErrorMessage;
});
message += "\n";
});
alert(message);
}
this is a tiny tweak to queen3's client side code which handles specific validation messages, and creates a similar document to that created by MVC3:
function getValidationSummary() {
var $el = $(".validation-summary-errors > ul");
if ($el.length == 0) {
$el = $("<div class='validation-summary-errors'><ul></ul></div>")
.hide()
.insertBefore('fieldset:first')
.find('ul');
}
return $el;
}
function getResponseValidationObject(response) {
if (response && response.Tag && response.Tag == "ValidationError")
return response;
return null;
}
function isValidationErrorResponse(response, form, summaryElement) {
var $list,
data = getResponseValidationObject(response);
if (!data) return false;
$list = summaryElement || getValidationSummary();
$list.html('');
$.each(data.State, function (i, item) {
var $val, lblTxt, errorList ="";
if (item.Name) {
$val = $(".field-validation-valid,.field-validation-error")
.first("[data-valmsg-for=" + item.Name + "]")
.removeClass("field-validation-valid")
.addClass("field-validation-error");
$("input[name=" + item.Name + "]").addClass("input-validation-error")
lblTxt = $("label[for=" + item.Name + "]").text();
if (lblTxt) { lblTxt += ": "; }
}
if ($val.length) {
$val.text(item.Errors.shift());
if (!item.Errors.length) { return; }
}
$.each(item.Errors, function (c,val) {
errorList += "<li>" + lblTxt + val + "</li>";
});
$list.append(errorList);
});
if ($list.find("li:first").length) {$list.closest("div").show(); }
return true;
}
See below for code with a few amendments to Brent's answer. CheckValidationErrorResponse looks for the Validation Summary regardless of whether it's in the valid or invalid state, and inserts it if not found. If validation errors are found in the response, it applies the validation-summary-errors class to the Summary, else it applies validation-summary-valid. It assumes CSS is present to control the visibility of the Summary.
The code clears existing instances of field-validation-error, and reapplies them for errors found in the response.
function getValidationSummary(form) {
var $summ = $(form).find('*[data-valmsg-summary="true"]');
if ($summ.length == 0)
{
$summ = $('<div class="validation-summary-valid" data-valmsg-summary="true"><ul></ul></div>');
$summ.appendTo(form);
}
return $summ;
}
function getValidationList(summary) {
var $list = $(summary).children('ul');
if ($list.length == 0) {
$list = $('<ul></ul>');
$list.appendTo(summary);
}
return $list;
}
function getResponseValidationErrors(data) {
if (data && data.ModelErrors && data.ModelErrors.length > 0)
return data.ModelErrors;
return null;
}
function CheckValidationErrorResponse(data, form, summaryElement) {
var errors = getResponseValidationErrors(data);
var $summ = summaryElement || getValidationSummary(form);
var $list = getValidationList($summ);
$list.html('');
$(form).find(".field-validation-error")
.removeClass("field-validation-error")
.addClass("field-validation-valid");
if (!errors)
{
$summ.removeClass('validation-summary-errors').addClass('validation-summary-valid');
return false;
}
$.each(errors, function (i, item) {
var $val, $input, errorList = "";
if (item.Name) {
$val = $(form).find(".field-validation-valid, .field-validation-error")
.filter("[data-valmsg-for=" + item.Name + "]")
.removeClass("field-validation-valid")
.addClass("field-validation-error");
$input = $(form).find("*[name='" + item.Name + "']");
if (!$input.is(":hidden") && !$val.length)
{
$input.parent().append("<span class='field-validation-error' data-valmsg-for='" + item.Name + "' data-valmsg-replace='false'>*</span>");
}
$input.addClass("input-validation-error");
}
$.each(item.Errors, function (c, err) {
errorList += "<li>" + err + "</li>";
});
$list.append(errorList);
});
$summ.removeClass('validation-summary-valid').addClass('validation-summary-errors');
return true;
}
C#
public class ValidateModelAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(HttpActionContext actionContext)
{
if (actionContext.ModelState.IsValid == false)
{
actionContext.Response = actionContext.Request.CreateErrorResponse(
HttpStatusCode.BadRequest, actionContext.ModelState);
}
}
}
JavaScript
$.ajax({
type: "GET",
url: "/api/xxxxx",
async: 'false',
error: function (xhr, status, err) {
if (xhr.status == 400) {
DisplayModelStateErrors(xhr.responseJSON.ModelState);
}
},
....
function DisplayModelStateErrors(modelState) {
var message = "";
var propStrings = Object.keys(modelState);
$.each(propStrings, function (i, propString) {
var propErrors = modelState[propString];
$.each(propErrors, function (j, propError) {
message += propError;
});
message += "\n";
});
alert(message);
};
If you are returning JSON, you cannot use ModelState. Everything that the view needs should be contained inside the JSON string. So instead of adding the error to the ModelState you could add it to the model you are serializing:
public ActionResult Index()
{
return Json(new
{
errorControl = "_FORM",
errorMessage = "Username or password is incorrect.",
someOtherProperty = "some other value"
});
}
I dont know if it is a SqlException or not but I will show you the source code:
//the update method
public int Update(T item) { int result = 0; var query = BuildUpdateQuery(item); if (query != null) result = query.Execute(); return result; }
/////////////////////////////////////////////////////////////
public ActionResult Edit(Employee item) { if(ModelState.IsValid) { string resultMessage = "";
try
{ _repository.Update(item); resultMessage = item.DescriptorValue() + " updated!"; }
catch(Exception x)
{ //edit this to return a message resultMessage = "ERROR: "+ item.DescriptorValue() + " failed: "+x.Message; }
//if this is an Ajax request - just send back a message if (Request.IsAjaxRequest())
{ return Content(resultMessage); }
else { return RedirectToAction("Index"); } }
else { return View(); } }
/////////////////////////////////////////////////////////////////
What do you want to know?
You have commented out the if clause asking if this is an Ajax Request. You probably want that on the next row...