Develop Reference

Adding object to JSON file

I'm creating a software on which I added a profiles feature where the user can create profile to load his informations faster. To store these informations, I'm using a JSON file, which contains as much objects as there are profiles.
Here is the format of the JSON file when a profile is contained (not the actual one, an example) :
{
"Profile-name": {
"form_email": "example#example.com",
//Many other informations...
}
}
Here is the code I'm using to write the JSON and its content :
string json = File.ReadAllText("profiles.json");
dynamic profiles = JsonConvert.DeserializeObject(json);
if (profiles == null)
{
File.WriteAllText(jsonFilePath, "{}");
json = File.ReadAllText(jsonFilePath);
profiles = JsonConvert.DeserializeObject<Dictionary<string, Profile_Name>>(json);
}
profiles.Add(profile_name.Text, new Profile_Name { form_email = form_email.Text });
var newJson = JsonConvert.SerializeObject(profiles, Formatting.Indented);
File.WriteAllText(jsonFilePath, newJson);
profile_tr.Nodes.Add(profile_name.Text, profile_name.Text);
debug_tb.Text += newJson;
But when the profiles.json file is completely empty, the profile is successfully written, but when I'm trying to ADD a profile when another one already exists, I get this error :
The best overloaded method match for 'Newtonsoft.Json.Linq.JObject.Add(string, Newtonsoft.Json.Linq.JToken)' has some invalid arguments on the profiles.Add(); line.
By the way, you can notice that I need to add {} by a non-trivial way in the file if it's empty, maybe it has something to do with the error ?
The expected output would be this JSON file :
{
"Profile-name": {
"form_email": "example#example.com",
//Many other informations...
},
"Second-profile": {
"form_email": "anotherexample#example.com"
//Some other informations...
}
}

Okay so I found by reading my code again, so I just replaced dynamic profiles = JsonConvert.DeserializeObject(json); to dynamic profiles = JsonConvert.DeserializeObject<Dictionary<string, Profile_Name>>(json);.
But it still don't fix the non-trivial way I use to add the {} to my file...

The object the first DeserializeObject method returns is actually a JObject, but below you deserialize it as a Dictionary. You shouldn't be mixing the types, choose either one.
If you use the JObject then to add objects you need to convert them to JObjects:
profiles.Add(profile_name.Text, JObject.FromObject(new Profile_Name { form_email = form_email.Text }));
In both cases, when the profile is null you just need to initialize it:
if (profiles == null)
{
profiles = new JObject(); // or new Dictionary<string, Profile_Name>();
}

How to make a model to carry only a boolean value without database?

I have a settings page and one of them is called "Enable News" And it have to return a boolean value
What i want to do is to carry the value of this field and call it again in another pages like
if (model.Boolean == true)
{
//Code
}
WITHOUT using database because this option is made for only 1 User
The purpose is to save this data in the model without database and be able to edit it later

Storing configurations can be done using XML, JSON and other formats according to the project requirements and what you're comfortable using.
JSON format is fairly simple if you have an object like
class UserSettings {
public bool EnableNews {get; set}
...
}
Then you can simple use Json.NET to store and retrieve an object of this class as follows:
var settings = new UserSettings();
settings.EnableNews = True;
....
string json = JsonConvert.SerializeObject(settings, Formatting.Indented);
//store it to file settings.json for example
//when you want to edit it you can load the file to string
string json_string = File.ReadAllText("file_path");
//then convert json string to model back to edit and read it
UserSettings userSettings = JsonConvert.DeserializeObject<UserSettings>(json_string);
for more details read Newtonsoft Json Package samples

Manage/Update Records in ASP.NET With Redis using ServiceStack

I'm coming from a SQL Server background, and experimenting with Redis in .NET using ServiceStack. I don't mean for Redis to be a full replacement for SQL Server, but I just wanted to get a basic idea of how to use it so I could see where we might make good use of it.
I'm struggling with what I think is a pretty basic issue. We have a list of items that are maintained in a couple of different data stores. For the sake of simplicity, assume the definition of the item is basic: an integer id and a string name. I'm trying to do the following:
Store an item
Retrieve an item if we only know its id
Overwrite an existing item if we only know its id
Show all the items for that specific type
And here's some of the code I've put together:
public class DocumentRepositoryRedis
{
private static string DOCUMENT_ID_KEY_BASE = "document::id::";
public IQueryable<Document> GetAllDocuments()
{
IEnumerable<Document> documentsFromRedis;
using (var documents = new RedisClient("localhost").As<Document>())
{
documentsFromRedis = documents.GetAll();
}
return documentsFromRedis.AsQueryable();
}
public Document GetDocument(int id)
{
Document document = null;
using (var redisDocuments = new RedisClient("localhost").As<Document>())
{
var documentKey = GetKeyByID(document.ID);
if (documentKey != null)
document = redisDocuments.GetValue(documentKey);
}
return document;
}
public void SaveDocument(Document document)
{
using (var redisDocuments = new RedisClient("localhost").As<Document>())
{
var documentKey = GetKeyByID(document.ID);
redisDocuments.SetEntry(documentKey, document);
}
}
private string GetKeyByID(int id)
{
return DOCUMENT_ID_KEY_BASE + id.ToString();
}
}
It all seems to work - except for GetAllDocuments. That's returning 0 documents, regardless of how many documents I have stored. What am I doing wrong?

The typed Redis client also gives you access to the non-typed methods - since Redis ultimately doesn't know or care about your object types. So when you use the client.SetEntry() method, it bypasses some of the typed client's features and just stores the object by a key. You'll want to use the client.Store method since it goes ahead and creates a SET in Redis with all the object IDs related to your type. This SET is important because it's what the GetAll method relies on to serve back all the objects to you. The client.Store method does infer the ID automatically so you'll want to play around with it.
You'd change your GetDocument(int id) and SaveDocument(Document document) methods to use the client.GetById(string id) method, and you'd use client.Store(T value) method. You won't need your GetKeyByID() method anymore. I believe your Document object will need an "Id" property for the typed client to infer your object ID.

storing JSON data in db

I'm trying to store data from fb wall into database.
My *.cs code
public ActionResult GetWall()
{
JSONObject wallData = helper.Get("/me/feed");
if (wallData != null)
{
var data = wallData.Dictionary["data"];
List<JSONObject> wallPosts = data.Array.ToList<JSONObject>();
ViewData["Wall"] = wallPosts;
}
return View("Index");
}
Which gets posts from fb wall.
And then I have an *.aspx file, which "breaks" my wallposts into pieces (objects) or whatever you like to call them.
foreach (Facebook.JSONObject wallItem in wallPosts)
{
string wallItemType = wallItem.Dictionary["type"].String;
//AND SO ON...
What i'm trying to say is that I can access to elements inside fb JSON.
Is there a way i can access to the JSON elements inside *.cs file.
Or is there a way I can store elements inside the *.aspx file to db?
And if its possible, I would like to know how. =)
Thanks for help

Don't use the SDK. Fetch the JSON Data using HttpWebRequest and then Deserialize it using System.Runtime.Serialization.Json.DataContractJsonSerializer. You just have to Create a class with same properties returned in JSON data. See the example below
string Response = Utilities.HttpUtility.Fetch("https://graph.facebook.com/me?access_token=" + AccessToken, "GET", string.Empty);
using (System.IO.MemoryStream oStream = new System.IO.MemoryStream(System.Text.Encoding.UTF8.GetBytes(Response)))
{
oStream.Position = 0;
return (Models.FacebookUser)new System.Runtime.Serialization.Json.DataContractJsonSerializer(typeof(Models.FacebookUser)).ReadObject(oStream);
}

I'm not familiar with the facebook API and the question isn't too clear, but I assume that the string wallItemType is itself a JSON string, and you wish to parse it.
I'd use the Json.Net library to parse this.
using Newtonsoft.Json;
//your code as above
foreach (Facebook.JSONObject wallItem in wallPosts)
{
string wallItemType = wallItem.Dictionary["type"].String;
//I assume wallItemType is a JSON string {"name":"foobar"} or similar
JObject o = JObject.Parse(wallItemType);
string name = (string)o["name"]; //returns 'foobar'
//and so on
you can also use the Json.Net to deserialize to a custom type. This custom type could be mapped to a SQL database using NHibernate.
If you wish to store the entire json string in a database, then you could use a document database such as CouchDB.

Persist data using JSON

I'm tryping to use JSON to update records in a database without a postback and I'm having trouble implementing it. This is my first time doing this so I would appreciate being pointed in the right direction.
(Explanation, irrelevant to my question: I am displaying a list of items that are sortable using a jquery plugin. The text of the items can be edited too. When people click submit I want their records to be updated. Functionality will be very similar to this.).
This javascript function creates an array of the objects. I just don't know what to do with them afterwards. It is called by the button's onClick event.
function SaveLinks() {
var list = document.getElementById('sortable1');
var links = [];
for (var i = 0; i < list.childNodes.length; i++) {
var link = {};
link.id = list.childNodes[i].childNodes[0].innerText;
link.title = list.childNodes[i].childNodes[1].innerText;
link.description = list.childNodes[i].childNodes[2].innerText;
link.url = list.childNodes[i].childNodes[3].innerText;
links.push(link);
}
//This is where I don't know what to do with my array.
}
I am trying to get this to call an update method that will persist the information to the database. Here is my codebehind function that will be called from the javascript.
public void SaveList(object o )
{
//cast and process, I assume
}
Any help is appreciated!

I have recently done this. I'm using MVC though it shouldn't be too different.
It's not vital but I find it helpful to create the contracts in JS on the client side and in C# on the server side so you can be sure of your interface.
Here's a bit of sample Javascript (with the jQuery library):
var item = new Item();
item.id = 1;
item.name = 2;
$.post("Item/Save", $.toJSON(item), function(data, testStatus) {
/*User can be notified that the item was saved successfully*/
window.location.reload();
}, "text");
In the above case I am expecting text back from the server but this can be XML, HTML or more JSON.
The server code is something like this:
public ActionResult Save()
{
string json = Request.Form[0];
var serializer = new DataContractJsonSerializer(typeof(JsonItem));
var memoryStream = new MemoryStream(Encoding.Unicode.GetBytes(json));
JsonItem item = (JsonItem)serializer.ReadObject(memoryStream);
memoryStream.Close();
SaveItem(item);
return Content("success");
}
Hope this makes sense.

You don't use CodeBehind for this, you use a new action.
Your action will take an argument which can be materialized from your posted data (which, in your case, is a JavaScript object, not JSON). So you'll need a type like:
public class Link
{
public int? Id { get; set; }
public string Title { get; set; }
public string Description { get; set; }
public string Url { get; set; }
}
Note the nullable int. If you have non-nullable types in your edit models, binding will fail if the user does not submit a value for that property. Using nullable types allows you to detect the null in your controller and give the user an informative message instead of just returning null for the whole model.
Now you add an action:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult DoStuff(IEnumerable<Link> saveList)
{
Repository.SaveLinks(saveList);
return Json(true);
}
Change your JS object to a form that MVC's DefaultModelBinder will understand:
var links = {};
for (var i = 0; i < list.childNodes.length; i++) {
links["id[" + i + "]"] = list.childNodes[i].childNodes[0].innerText;
links["title[" + i + "]"] = list.childNodes[i].childNodes[1].innerText;
links["description[" + i + "]"] = list.childNodes[i].childNodes[2].innerText;
links["url[" + i + "]"] = list.childNodes[i].childNodes[3].innerText;
}
Finally, call the action in your JS:
//This is where I don't know what to do with my array. Now you do!
// presumes jQuery -- this is much easier with jQuery
$.post("/path/to/DoStuff", links, function() {
// success!
},
'json');

Unfortunately, JavaScript does not have a built-in function for serializing a structure to JSON. So if you want to POST some JSON in an Ajax query, you'll either have to munge the string yourself or use a third-party serializer. (jQuery has a a plugin or two that does it, for example.)
That said, you usually don't need to send JSON to the HTTP server to process it. You can simply use an Ajax POST request and encode the form the usual way (application/x-www-form-urlencoded).
You can't send structured data like nested arrays this way, but you might be able to get away with naming the fields in your links structure with a counter. (links.id_1, links.id_2, etc.)
If you do that, then with something like jQuery it's as simple as
jQuery.post( '/foo/yourapp', links, function() { alert 'posted stuff' } );
Then you would have to restructure the data on the server side.