C#•4mo ago

Seeding Data Into Database

Hello there, I'm still new to asp.net and i've been learning through a course on this Course. At episode 83. they were talking about seeding data into database but when i tried to apply the code they used i had an error about the required fields being null the data are random generated in a .json file.

5 Replies

Al3mid3xOP•4mo ago

User:

c#
using API.Extensions;

namespace API.Entities
{
    public class User
    {
        public int Id{ get; set; }

        public required string UserName{ get; set; }
        public required byte[] PasswordHash { get; set; } = [];
        public required byte[] PasswordSalt { get; set; } = [];

        public DateOnly DateOfBirth { get; set; }
        public required string KnownAs{ get; set; }
        public DateTime Created { get; set; } = DateTime.UtcNow;
        public DateTime LastActive { get; set; } = DateTime.UtcNow;

        public required string Gender { get; set; }
        public string? Introduction { get; set; }
        public string? Interests { get; set; }
        public string? LookingFor { get; set; }

        public required string City {  get; set; }
        public required string Country { get; set; }
        public List<Photo> Photos { get; set; }

        public int GetAge()
        {
            return DateOfBirth.CalculateAge();
        }
    }
}

c#
using API.Extensions;

namespace API.Entities
{
    public class User
    {
        public int Id{ get; set; }

        public required string UserName{ get; set; }
        public required byte[] PasswordHash { get; set; } = [];
        public required byte[] PasswordSalt { get; set; } = [];

        public DateOnly DateOfBirth { get; set; }
        public required string KnownAs{ get; set; }
        public DateTime Created { get; set; } = DateTime.UtcNow;
        public DateTime LastActive { get; set; } = DateTime.UtcNow;

        public required string Gender { get; set; }
        public string? Introduction { get; set; }
        public string? Interests { get; set; }
        public string? LookingFor { get; set; }

        public required string City {  get; set; }
        public required string Country { get; set; }
        public List<Photo> Photos { get; set; }

        public int GetAge()
        {
            return DateOfBirth.CalculateAge();
        }
    }
}

Exception

fail: Program[0]
      An error occurred during migration
      System.Text.Json.JsonException: JSON deserialization for type 'API.Entities.User' was missing required properties, including the following: PasswordHash, PasswordSalt
         at System.Text.Json.ThrowHelper.ThrowJsonException_JsonRequiredPropertyMissing(JsonTypeInfo parent, BitArray requiredPropertiesSet)
         at System.Text.Json.Serialization.Converters.ObjectDefaultConverter`1.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
         at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
         at System.Text.Json.Serialization.JsonCollectionConverter`2.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, TCollection& value)
         at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
         at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
         at System.Text.Json.JsonSerializer.ReadFromSpan[TValue](ReadOnlySpan`1 utf8Json, JsonTypeInfo`1 jsonTypeInfo, Nullable`1 actualByteCount)
         at System.Text.Json.JsonSerializer.ReadFromSpan[TValue](ReadOnlySpan`1 json, JsonTypeInfo`1 jsonTypeInfo)
         at System.Text.Json.JsonSerializer.Deserialize[TValue](String json, JsonSerializerOptions options)
         at API.Data.Seed.SeedUsers(DataContext context) in C:\Users\pc\source\repos\DatingApp\API\Data\Seed.cs:line 19
         at Program.<Main>$(String[] args) in C:\Users\pc\source\repos\DatingApp\API\Program.cs:line 30

fail: Program[0]
      An error occurred during migration
      System.Text.Json.JsonException: JSON deserialization for type 'API.Entities.User' was missing required properties, including the following: PasswordHash, PasswordSalt
         at System.Text.Json.ThrowHelper.ThrowJsonException_JsonRequiredPropertyMissing(JsonTypeInfo parent, BitArray requiredPropertiesSet)
         at System.Text.Json.Serialization.Converters.ObjectDefaultConverter`1.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
         at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
         at System.Text.Json.Serialization.JsonCollectionConverter`2.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, TCollection& value)
         at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
         at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
         at System.Text.Json.JsonSerializer.ReadFromSpan[TValue](ReadOnlySpan`1 utf8Json, JsonTypeInfo`1 jsonTypeInfo, Nullable`1 actualByteCount)
         at System.Text.Json.JsonSerializer.ReadFromSpan[TValue](ReadOnlySpan`1 json, JsonTypeInfo`1 jsonTypeInfo)
         at System.Text.Json.JsonSerializer.Deserialize[TValue](String json, JsonSerializerOptions options)
         at API.Data.Seed.SeedUsers(DataContext context) in C:\Users\pc\source\repos\DatingApp\API\Data\Seed.cs:line 19
         at Program.<Main>$(String[] args) in C:\Users\pc\source\repos\DatingApp\API\Program.cs:line 30

Al3mid3xOP•4mo ago

Json data file

message.txt

Al3mid3xOP•4mo ago

Seed Class

c#
using API.Entities;
using Microsoft.EntityFrameworkCore;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;

namespace API.Data
{
    public class Seed
    {
        public static async Task SeedUsers(DataContext context)
        {
            if (await context.Users.AnyAsync()) return;

            var userData = await File.ReadAllTextAsync("Data/UserSeedData.json");

            var options = new JsonSerializerOptions { PropertyNameCaseInsensitive = true };

            var users = JsonSerializer.Deserialize<List<User>>(userData, options);

            if(users == null) return;

            foreach (var user in users) {
                using var hmac = new HMACSHA512();

                user.UserName = user.UserName.ToLower();
                user.PasswordHash = hmac.ComputeHash(Encoding.UTF8.GetBytes("Pa$$w0rd"));
                user.PasswordSalt = hmac.Key;

                context.Users.Add(user);
                
            }
            await context.SaveChangesAsync();
        }
    }
}

c#
using API.Entities;
using Microsoft.EntityFrameworkCore;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;

namespace API.Data
{
    public class Seed
    {
        public static async Task SeedUsers(DataContext context)
        {
            if (await context.Users.AnyAsync()) return;

            var userData = await File.ReadAllTextAsync("Data/UserSeedData.json");

            var options = new JsonSerializerOptions { PropertyNameCaseInsensitive = true };

            var users = JsonSerializer.Deserialize<List<User>>(userData, options);

            if(users == null) return;

            foreach (var user in users) {
                using var hmac = new HMACSHA512();

                user.UserName = user.UserName.ToLower();
                user.PasswordHash = hmac.ComputeHash(Encoding.UTF8.GetBytes("Pa$$w0rd"));
                user.PasswordSalt = hmac.Key;

                context.Users.Add(user);
                
            }
            await context.SaveChangesAsync();
        }
    }
}

the error is happining because of the PasswordHash and PasswordSalt are not modified in the json folder but you can see that i have given them a value in the seed class and they already have a default value of an empty array in the User.cs class

Omnissiah•4mo ago

have you empirically tried to have those field in the json like

{
  "PasswordHash": ""
  ...
}

{
  "PasswordHash": ""
  ...
}

or even "PasswordHash": null i think it works i don't know how required behave with stj but maybe it's more strict than that

Gokul•4mo ago

the issue is in the User class you have marked PasswordHash and PasswordSalt as required, which means during deserialization it will expect a value to be present in the json, it doesnt matter if you set the values later on inside a for loop, the error states during deserialization its unable to find PasswordHash and PasswordSalt values . try removing required from User class and handling the required logic through code, else add empty string in json like "PasswordHash":"", "PasswordSalt":""

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