C#•16mo ago

Update JSON File with new values without overwriting existing data

Hello, So I'm currently developing a Discord bot that stores values such as 'settings' for each guild. I already got that part figured out very well but I would like to know how I should handle additions / removes. I have a class as followed:

        public class GuildConfiguration
        {
            public string GuildPrefix { get; set; } = default!;
            public bool EnableModeratorNotifications { get; set; } = default!;
            public GuildCommandPermissions GuildCommandPermissions { get; set; } = default!;
        }

        public class GuildConfiguration
        {
            public string GuildPrefix { get; set; } = default!;
            public bool EnableModeratorNotifications { get; set; } = default!;
            public GuildCommandPermissions GuildCommandPermissions { get; set; } = default!;
        }

As an example, currently, the json file doesn't have the public bool EnableModeratorNotifications included but it is a new feature I would like to add. If I add that to my class, how would I serialize it into the json file with a default value like true/false without overwriting the existing values there?

46 Replies

jcotton42•16mo ago

are you deserializing the JSON into an instance of that before writing it back out?

Kye•16mo ago

Yes.

jcotton42•16mo ago

I think system.text.json will just use the default value then (btw, you don't need ! on that bool, that's only for nullable ref types)

Kye•16mo ago

ah okay

jcotton42•16mo ago

also, if you want those props to always be set, you might want

public required string GuildPrefix { get; set; }

public required string GuildPrefix { get; set; }

instead

Kye•16mo ago

What does 'required' specifically do?

jcotton42•16mo ago

the compiler yells at you if you try to create an instance without setting that prop

MODiX•16mo ago

jcotton42#1663

REPL Result: Failure

class GuildSettings {
  public required string GuildPrefix { get; set; }
}
var settings = new GuildSettings();

class GuildSettings {
  public required string GuildPrefix { get; set; }
}
var settings = new GuildSettings();

Exception: CompilationErrorException

- Required member 'GuildSettings.GuildPrefix' must be set in the object initializer or attribute constructor.

- Required member 'GuildSettings.GuildPrefix' must be set in the object initializer or attribute constructor.

Compile: 489.636ms | Execution: 0.000ms | React with ❌ to remove this embed.

Kye•16mo ago

ah okay makes sense

MODiX•16mo ago

jcotton42#1663

REPL Result: Success

class GuildSettings {
  public required string GuildPrefix { get; set; }
}
var settings = new GuildSettings() { GuildPrefix = "foo" };

class GuildSettings {
  public required string GuildPrefix { get; set; }
}
var settings = new GuildSettings() { GuildPrefix = "foo" };

Compile: 553.507ms | Execution: 56.267ms | React with ❌ to remove this embed.

Kye•16mo ago

So, I heard about [JsonProperty(DefaultValueHandling = DefaultValueHandling.Populate)] and DefaultValue() would that do something? or could I basically do public string GuildPrefix { get; set; } = "Value Here";

jcotton42•16mo ago

that looks like Newtonsoft? are you using newtonsoft, or system.text.json?

Kye•16mo ago

I think it is Newtonsoft if I am not mistaken Yep, it's Newtonsoft.Json;

jcotton42•16mo ago

I'm not familiar with that part of it I always use STJ

Kye•16mo ago

Is there a benefit of using STJ over Newtonsoft?

jcotton42•16mo ago

faster, lower memory usage, etc. Newtonsoft has more features, but I don't find myself needing them it's also one less dependency to bundle, if you care about that

Kye•16mo ago

oh, i did hear about STJ but I somehow always ended up using Newtonsoft.Json I will try your advice and check

jcotton42•16mo ago

in any case, here's how STJ works by default

JsonConvert.DeserializeObject<GuildConfiguration>("""
{
    "GuildPrefix": "foo",
    "GuildCommandPermissions": 3
}
""").Dump();

public class GuildConfiguration
{
    public string GuildPrefix { get; set; }
    public bool EnableModeratorNotifications { get; set; } = true;
    public int GuildCommandPermissions { get; set; }
}

JsonConvert.DeserializeObject<GuildConfiguration>("""
{
    "GuildPrefix": "foo",
    "GuildCommandPermissions": 3
}
""").Dump();

public class GuildConfiguration
{
    public string GuildPrefix { get; set; }
    public bool EnableModeratorNotifications { get; set; } = true;
    public int GuildCommandPermissions { get; set; }
}

jcotton42•16mo ago

gives

Kye•16mo ago

Oh, so it serializes on it's own basically?

jcotton42•16mo ago

err, oops meant NewtonSoft pretty sure STJ is the same, lemme try

Kye•16mo ago

ohh

jcotton42•16mo ago

oh huh

jcotton42•16mo ago

I bet that's configurable...

Kye•16mo ago

Hm I see

jcotton42•16mo ago

https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/required-properties

Require properties for deserialization

Learn how to mark properties as required for deserialization to succeed.

jcotton42•16mo ago

yeah that's intended

Kye•16mo ago

For some reason, for me .Dump(); isn't available

jcotton42•16mo ago

ah sorry that's a LINQPad thing it's writes to the lower pane

Kye•16mo ago

oh okay Instead of a string, is it possible to deserialize the object using a path to the json file? Because if so, I would simply add it to my loop when checking if each guild has the appropriate json file if it exists, simply update it

jcotton42•16mo ago

STJ can take a stream to deserialize it looks like NewtonSoft can't, which is surprising so you'd need to read the file into memory as a string then deserialize

Kye•16mo ago

So like this,

    string guildJson = File.ReadAllText($"app1000/guilds/{getGuild.Id}/guilddata.json");
    JsonConvert.DeserializeObject<GuildInformation>(guildJson);

    string guildJson = File.ReadAllText($"app1000/guilds/{getGuild.Id}/guilddata.json");
    JsonConvert.DeserializeObject<GuildInformation>(guildJson);

jcotton42•16mo ago

yeah

Kye•16mo ago

I did but for some reason the new value wasn't added to the json

jcotton42•16mo ago

well, you're only deserializing you're not serializing back to it (also, if you're not that far in, you might want to consider using a database; managing tons of json files will get hairy pretty fast)

Kye•16mo ago

oop i was told that json can be pretty tough but i get it, im deserializing it but i have to serialize it back

jcotton42•16mo ago

it's not "json is tough" it's "when you have a ton of files spread about you're poorly approximating a database"

Kye•16mo ago

I would use a database since I have worked with MySQL before a lot

jcotton42•16mo ago

for a bot I'd use something like SQLite or PostgreSQL (I have... opinions about MySQL, tbh) EF Core makes interfacing with the db pretty easy

Kye•16mo ago

The bot would handle a lot of cases at once and im not sure how the performance would be for the bot like, i once added a leveling system which means everytime a user types a message, it would change his score in the json which worked fine

jcotton42•16mo ago

databases are obscenely fast even sqlite

Kye•16mo ago

Would that mean I have to keep the connection to the database open 24/7 once it's open hm i see

jcotton42•16mo ago

if you use EF it manages the connection for you I haven't done it manually in a long while

Kye•16mo ago

i haven't worked with a DB in awhile yeah I still can't seem to figure out how to update the json file Setting a default value in the designer class works fine but actually adding that value into the json file doesn'twork :/ Nevermind, it worked using this code:

var getGuildDataPath = File.ReadAllText($"app1000/guilds/{getGuild.Id}/guilddata.json");
var getGuildData = JsonConvert.DeserializeObject<GuildInformation>(getGuildDataPath);

var updateGuildFile = JsonConvert.SerializeObject(getGuildData, Formatting.Indented);
File.WriteAllText($"app1000/guilds/{getGuild.Id}/guilddata.json", updateGuildFile);

var getGuildDataPath = File.ReadAllText($"app1000/guilds/{getGuild.Id}/guilddata.json");
var getGuildData = JsonConvert.DeserializeObject<GuildInformation>(getGuildDataPath);

var updateGuildFile = JsonConvert.SerializeObject(getGuildData, Formatting.Indented);
File.WriteAllText($"app1000/guilds/{getGuild.Id}/guilddata.json", updateGuildFile);

I mean this looks kinda weird but it works?

jcotton42•16mo ago

I mean how else would you expect it to work? you deserialize to an object update the object serialize back

Kye•16mo ago

Well, tbh, this looks like sloppy work. I usually look at the code in a more clean way but this will do.

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Update JSON File with new values without overwriting existing data