I'm looking for fast string concatenation class or so in Flex.
Like StringBuilder in Java.
Thanks
var str1:String = "Vinoth";
var str2:String = "Babu";
var str3:String = "Chennai";
var str4:String = concat(str1, " ", str2, " ", str3)
trace(str4) would result you
str4 == "Vinoth babu Chennai"
String Concat Class
public class StringBuffer
{
public var buffer:Array = new Array();
public function add(str:String):void
{
for (var i:Number = 0; i < str.length; i++)
{
buffer.push(str.charCodeAt(i));
}
}
public function toString():String
{
return String.fromCharCode.apply(this, buffer);
}
}
Here you have a more indepth than the above class written.
http://blogs.adobe.com/pfarland/2007/10/avoiding_string_concatenation.html
You can create an array of strings and then use String.concat to combine them.
However, I've never seen string manipulation come up as a bottleneck when profiling a Flex app. I have in .NET, but not Flex.
Related
I'm developing a project that will require me to include credentials for things like an SMTP server. I'd like to store this information along with the complete details of the endpoint in an embedded JSON file, but I would like to have that information encrypted and then let my application decrypt it when it needs to establish a connection and log in. The JSON structure looks something like this:
{
"Endpoints" : [
{
"Endpoint" : {
"Host": "smtp.mydomain.tld",
"Port": 587,
"Username": "user#mydomain.tld",
"Password": "mYp#s$w0?d"
}
}
]
}
While what I'd really like to have actually stored in the file would look something like this:
{
"Endpoints" : [
{
"Endpoint" : "<BASE64_ENCODED_STRING>"
}
]
}
Using Newtonsoft's Json.NET, I've built the class object/properties to desriealize this structure:
<JsonProperty("Endpoints")>
Public Property Endpoints As List(Of EndpointContainer) = Nothing
Public Class EndpointContainer
<EditorBrowsable(EditorBrowsableState.Never)> <DebuggerBrowsable(DebuggerBrowsableState.Never)>
Private Const EncryptedPrefix As String = "myappcipher:"
<EditorBrowsable(EditorBrowsableState.Never)> <DebuggerBrowsable(DebuggerBrowsableState.Never)>
<JsonProperty("Endpoint")> <JsonConverter(GetType(EndpointProtector))>
Public Property Endpoint As Endpoint = Nothing
End Class
And I've built the inherited JsonConverter class ("EndpointProtector") like this:
Public Class EndpointProtector
Inherits JsonConverter
Public Sub New()
Using SHAEncryption = New SHA256Managed()
_EncryptionKey = SHAEncryption.ComputeHash(Encoding.UTF8.GetBytes(TestEncryptionKey))
End Using
End Sub
Public Overrides Sub WriteJson(writer As JsonWriter, value As Object, serializer As JsonSerializer)
Dim clearText As String = JsonConvert.SerializeObject(value)
If clearText Is Nothing Then
Throw New ArgumentNullException(NameOf(clearText))
End If
writer.WriteValue(EncryptEndpoint(clearText))
End Sub
Public Overrides Function ReadJson(reader As JsonReader, objectType As Type, existingValue As Object, serializer As JsonSerializer) As Object
Dim DecryptString As String = TryCast(reader.Value, String)
If String.IsNullOrEmpty(DecryptString) Then
Return reader.Value
ElseIf Not DecryptString.StartsWith(EncryptedPrefix, StringComparison.OrdinalIgnoreCase) Then
Return DecryptString
Else
Return DecryptEndpoint(DecryptString)
End If
End Function
Public Overrides Function CanConvert(objectType As Type) As Boolean
Throw New NotImplementedException()
End Function
End Class
Currently I have the JSON file itself with the full object definition (as in the first code block). When my application reads that JSON, it correctly moves to the overridden ReadJson() method I have, but the reader.Value is null (Nothing), so it never actually gets to the DecryptEndpoint() method. Of course, that means there's nothing to encrypt, so the application won't even step into the WriteJson() method.
I've tried a couple of variations, including making the Endpoint property into a private variable with a generic Object type, and then having a separate public property with the <JsonIgnore> decoration to "read" from that, but nothing seems to get me where I need to be. I'm sure I'm overlooking something here, but I can't seem to figure out why it's not getting anything at all.
I looked at a few other SO questions like Encrypt and JSON Serialize an object, but I've still not yet been able to figure out quite where I've gone wrong here.
NOTE: I intentionally didn't include the code for the EncryptEndpoint() or DecryptEndpoint() methods here simply because the code is never making it that far in the process. If you feel it's needed to fully answer the question, please let me know.
this is a linqpad example of working encrypt/decrypt base on JsonAttribute
void Main()
{
string str = "";
var t = new Test() { encName = "some long text some long text some long text", Name = "test" };
JsonSerializerSettings theJsonSerializerSettings = new JsonSerializerSettings();
theJsonSerializerSettings.TypeNameHandling = TypeNameHandling.None;
str = JsonConvert.SerializeObject(t, theJsonSerializerSettings).Dump();
JsonConvert.DeserializeObject<Test>(str, theJsonSerializerSettings).Dump();
}
public class Test
{
[JsonConverter(typeof(EncryptingJsonConverter))]
public string encName { get; set; }
public string Name { get; set; }
}
/// <summary>[JsonConverter(typeof(EncryptingJsonConverter), string 32byte array)]</summary>
public class EncryptingJsonConverter : JsonConverter
{
private readonly byte[] _encryptionKeyBytes;
private readonly string _encryptionKeyString;
///<summary>Key must be 32char length</summary>
public EncryptingJsonConverter()
{
string encryptionKey = "E546C8DF278CD5931069B522E695D4F2"; //get from config
if (string.IsNullOrEmpty(encryptionKey))
throw new ArgumentNullException(nameof(encryptionKey));
_encryptionKeyString = encryptionKey;
_encryptionKeyBytes = Convert.FromBase64String(encryptionKey);
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var stringValue = (string)value;
if (string.IsNullOrEmpty(stringValue))
{
writer.WriteNull();
return;
}
//string enc = stringValue.Encrypt(_encryptionKeyString);
string enc = Crypto.Encrypt(stringValue, _encryptionKeyBytes);
writer.WriteValue(enc);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var value = reader.Value as string;
if (string.IsNullOrEmpty(value))
return reader.Value;
try
{
//return value.Decrypt(_encryptionKeyString);
return Crypto.Decrypt(value, _encryptionKeyBytes);
}
catch
{
return string.Empty;
}
}
/// <inheritdoc />
public override bool CanConvert(Type objectType)
{
return objectType == typeof(string);
}
}
public static class Crypto
{
public static string Encrypt(this string text, string key)
{
if (string.IsNullOrEmpty(key))
throw new ArgumentException("Key must have valid value.", nameof(key));
if (string.IsNullOrEmpty(text))
throw new ArgumentException("The text must have valid value.", nameof(text));
var buffer = Encoding.UTF8.GetBytes(text);
var hash = SHA512.Create();
var aesKey = new byte[24];
Buffer.BlockCopy(hash.ComputeHash(Encoding.UTF8.GetBytes(key)), 0, aesKey, 0, 24);
using (var aes = Aes.Create())
{
if (aes == null)
throw new ArgumentException("Parameter must not be null.", nameof(aes));
aes.Key = aesKey;
using (var encryptor = aes.CreateEncryptor(aes.Key, aes.IV))
using (var resultStream = new MemoryStream())
{
using (var aesStream = new CryptoStream(resultStream, encryptor, CryptoStreamMode.Write))
using (var plainStream = new MemoryStream(buffer))
{
plainStream.CopyTo(aesStream);
}
var result = resultStream.ToArray();
var combined = new byte[aes.IV.Length + result.Length];
Array.ConstrainedCopy(aes.IV, 0, combined, 0, aes.IV.Length);
Array.ConstrainedCopy(result, 0, combined, aes.IV.Length, result.Length);
return Convert.ToBase64String(combined);
}
}
}
public static string Decrypt(this string encryptedText, string key)
{
if (string.IsNullOrEmpty(key))
throw new ArgumentException("Key must have valid value.", nameof(key));
if (string.IsNullOrEmpty(encryptedText))
throw new ArgumentException("The encrypted text must have valid value.", nameof(encryptedText));
var combined = Convert.FromBase64String(encryptedText);
var buffer = new byte[combined.Length];
var hash = new SHA512CryptoServiceProvider();
var aesKey = new byte[24];
Buffer.BlockCopy(hash.ComputeHash(Encoding.UTF8.GetBytes(key)), 0, aesKey, 0, 24);
using (var aes = Aes.Create())
{
if (aes == null)
throw new ArgumentException("Parameter must not be null.", nameof(aes));
aes.Key = aesKey;
var iv = new byte[aes.IV.Length];
var ciphertext = new byte[buffer.Length - iv.Length];
Array.ConstrainedCopy(combined, 0, iv, 0, iv.Length);
Array.ConstrainedCopy(combined, iv.Length, ciphertext, 0, ciphertext.Length);
aes.IV = iv;
using (var decryptor = aes.CreateDecryptor(aes.Key, aes.IV))
using (var resultStream = new MemoryStream())
{
using (var aesStream = new CryptoStream(resultStream, decryptor, CryptoStreamMode.Write))
using (var plainStream = new MemoryStream(ciphertext))
{
plainStream.CopyTo(aesStream);
}
return Encoding.UTF8.GetString(resultStream.ToArray());
}
}
}
public static string Encrypt(string text, byte[] key)
{
//string keyString = "encrypt123456789";
//var key = Encoding.UTF8.GetBytes(keyString);//16 bit or 32 bit key string
using (var aesAlg = Aes.Create())
{
using (var encryptor = aesAlg.CreateEncryptor(key, aesAlg.IV))
{
using (var msEncrypt = new MemoryStream())
{
using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
using (var swEncrypt = new StreamWriter(csEncrypt))
{
swEncrypt.Write(text);
}
var iv = aesAlg.IV;
var decryptedContent = msEncrypt.ToArray();
var result = new byte[iv.Length + decryptedContent.Length];
Buffer.BlockCopy(iv, 0, result, 0, iv.Length);
Buffer.BlockCopy(decryptedContent, 0, result, iv.Length, decryptedContent.Length);
return Convert.ToBase64String(result);
}
}
}
}
public static string Decrypt(string cipherText, byte[] key)
{
var fullCipher = Convert.FromBase64String(cipherText);
var iv = new byte[16];
var cipher = new byte[fullCipher.Length - iv.Length];//new byte[16];
Buffer.BlockCopy(fullCipher, 0, iv, 0, iv.Length);
Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, cipher.Length);
//var key = Encoding.UTF8.GetBytes(keyString);//same key string
using (var aesAlg = Aes.Create())
{
using (var decryptor = aesAlg.CreateDecryptor(key, iv))
{
string result;
using (var msDecrypt = new MemoryStream(cipher))
{
using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (var srDecrypt = new StreamReader(csDecrypt))
{
result = srDecrypt.ReadToEnd();
}
}
}
return result;
}
}
}
}
to activate encryption just add a tag
[JsonConverter(typeof(EncryptingJsonConverter))]
How can I change the casing of the property names of a json without performing model binding?
JsonElement serialization ignores PropertyNaming JsonSerializer options as is also confirmed here: https://github.com/dotnet/runtime/issues/61843
The suggested use of JsonNode/JsonObject results in the same behavior.
Any hints how I can accomplish this?
As example I want to change this:
{
"MyPoperty" : 5,
"MyComplexProperty" : {
"MyOtherProperty": "value",
"MyThirdProperty": true
}
}
to this:
{
"myPoperty" : 5,
"myComplexProperty" : {
"myOtherProperty": "value",
"myThirdProperty": true
}
}
Cheers.
I think you try to use Newtonsoft json
class Person
{
public string UserName { get; set; }
public int Age { get; set; }
}
coding
static void Main(string[] args)
{
Person person = new Person();
person.UserName = "Bob";
person.Age = 20;
var serializerSettings = new JsonSerializerSettings();
serializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
var json = JsonConvert.SerializeObject(person, serializerSettings);
Console.WriteLine(json);
}
output
{"userName":"Bob","age":20}
not depend on Newtonsoft json but in the case of multi-layer objects
var json = #"{""ShouldWindUpAsCamelCase"":""does it?""}";
var obj = JsonSerializer.Deserialize<Dictionary<string,string>>(json);
var dic = new Dictionary<string, string>();
foreach (var item in obj)
{
dic.Add(item.Key.FirstCharToLower(), item.Value);
}
var serialized = System.Text.Json.JsonSerializer.Serialize(dic);
Console.WriteLine(serialized);
FirstCharToLower() function
public static string FirstCharToLower(this string input)
{
if (String.IsNullOrEmpty(input))
return input;
string str = input.First().ToString().ToLower() + input.Substring(1);
return str;
}
#output
{"shouldWindUpAsCamelCase":"does it?"}
I have an JSON array as defined below:-
[
{"Name":"Ayush","Age":24,"Job":"Developer"},
{"Name":"Monika","Age":23,"Job":"Developer"},
{"Name":"Chinmay","Age":23,"Job":"Developer"}
]
I want to dump this into text file in following format:-
Name Age Job
Ayush 24 Developer
Monika 23 Developer
Chinmay 23 Developer
Is there any C# function to accomplish the above? If not, how can i achieve it with minimum memory consumption?
Thanks in advance
There is no such built-in function. You may achieve this by reading JTokens from input stream using JsonTextReader and writing their values into another stream. Stream input and output ensures minimal memory footprint.
using (var inputStream = File.OpenRead("input.json"))
using (var streamReader = new StreamReader(inputStream))
using (var jsonTextReader = new JsonTextReader(streamReader))
using (var outputStream = File.OpenWrite("output.csv"))
using (var streamWriter = new StreamWriter(outputStream))
{
var firstItem = true;
while (jsonTextReader.Read())
{
if (jsonTextReader.TokenType == JsonToken.StartObject)
{
var jObject = JObject.ReadFrom(jsonTextReader);
if (firstItem)
{
streamWriter.WriteLine(string.Join("\t",
jObject.Children().Select(c => (c as JProperty).Name)));
firstItem = false;
}
streamWriter.WriteLine(string.Join("\t",
jObject.Values().Select(t => t.ToString())));
}
}
}
Demo: https://dotnetfiddle.net/2fCRa6. (I used MemoryStream and Console instead of input and output file streams in this demo since .NET Fiddle does not allow file IO, but the idea is the same.)
You can create a class with Name, Age and Job as properties.
public class Info{
public string Name { get; set; }
public int Age { get; set; }
public string Job { get; set; }
}
Then in another function use we can use System.Web.Script.Serialization class(to use this class make sure you have referenced System.Web.Extensions in project references). Once done we can use JavaScriptSerializer class and get list of objects from the json data. Then we can iterate over each item and add it two our file with a tab as a delimeter.
public static void WriteDetailsInFile(string jsonData)
{
var list = new JavaScriptSerializer().Deserialize<List<Info>>(jsonData);
using (var streamWriter = File.AppendText("D:MyFile.txt"))
{
streamWriter.WriteLine("Name\tAge\tJob");
foreach (var item in list)
{
streamWriter.WriteLine(item.Name + "\t" + item.Age + "\t" + item.Job);
}
}
}
//driver
public static void Main()
{
string data = #"[
{ ""Name"":""Ayush"",""Age"":24,""Job"":""Developer""},
{ ""Name"":""Monika"",""Age"":23,""Job"":""Developer""},
{ ""Name"":""Chinmay"",""Age"":23,""Job"":""Developer""}
]";
WriteDetailsInFile(data);
}
I'm new to AS3 and I'm getting this error while trying to implement OO style code.
Incorrect number of arguments. Expected no more than 0.
When I try to:
var countries:Country = new Country(10);
Normally this would work in Java or C++, so I'm not sure what's up!?
Here is my custom class.
package {
public class Country {
var cName:String = "noName";
public function Country() {
// constructor code
}
public function setName(n:String):void {
cName = n;
}
public function getName():String {
return cName;
}
}
}
You are passing 10 to the constructor, which is not what you want to do. To instantiate an array of instances, try something like this:
var countries:Array = []
var country:Country;
for (var i:uint = 0; i < 10; i++) {
country = new Country()
country.setName("Country_" + i);
countries.push(country)
}
your constructor function public function Country() {} not have an argument, but you give 10, must go wrong.
ActionScript's array not like c++, don't need element type <Country>
you want to save class in array is simple: var arr:Array = [new Country()]
Is it possible to make the LINQ SELECT more flexible by not working with properties but with the column name?
Maybe an example will help..I'm trying to do the following (pseudocode):
From x In Entities
Where ...
Select("ID", "Value" , "Date")
but depending on certain choices, I would like to have the result in different order
From x In Entities
Where ...
Select("Value", "Date", "ID" )
Or another amount of SELECT results
From x In Entities
Where ...
Select("Value")
Any help to make this as dynamic as possible would be AWESOME! tnx
Maybe this will help you
from x In Entities
where ... select new {
Value = x["Value"],
Date = x["Date"],
ID = x["ID"]
}
Like I said in my comment (handles subproperties, like Type.Name, but not multiple fields)
I let the fun to make the multi field version ;)
public static class DynamicLinkExtensions
{
public static IEnumerable<dynamic> Select<T>(this IQueryable<T> source, string memberAccess)
{
var propNames = memberAccess.Split('.');
var type = typeof(T);
var props = new List<PropertyInfo>();
foreach (var propName in propNames)
{
var prop = type.GetProperty(propName);
props.Add(prop);
type = prop.PropertyType;
}
return source.Select(props.ToArray());
}
public static IEnumerable<dynamic> Select<T>(this IQueryable<T> source, PropertyInfo[] props)
{
var parameter = Expression.Parameter(typeof(T));
var member = Expression.MakeMemberAccess(parameter, (MemberInfo)props.First());
for (var i = 1; i < props.Length; i++)
{
member = Expression.MakeMemberAccess(member, (MemberInfo)props[i]);
}
Expression<Func<T, object>> expression = Expression.Lambda<Func<T, object>>(member, new[] { parameter });
return source.Select(expression);
}
}
Usage:
var names = DataContext.Customers.Select("Name").Cast<string>().ToList();