How to deserialize xml using XmlArrayItem - asp.net

I want to deserialize xml like this:
<Product>
<Classification>
<NewClassification>1</NewClassification>
<NewClassification>2</NewClassification>
<NewClassification>3</NewClassification>
<OldClassification>A</OldClassification>
<OldClassification>B</OldClassification>
</Classification>
</Product>
My classes are:
public class Product
{
public Classification Classification { get; set; }
}
public class Classification
{
[XmlArrayItem(typeof(int), ElementName = "NewClassification")]
public List<int> NewClassificationList { get; set; }
[XmlArrayItem(typeof(int), ElementName = "OldClassification")]
public List<int> OldClassificationList { get; set; }
}
Why this code is wrong?

Apart from the "int literal" issue commented on by "Bears will eat you" above, you can't serialize your class in the way you want with what you've got (at least I can't think of a way to do it)
without resorting to custom serialisation (e.g. implementing IXmlSerializable or some other method).
Your basic problem is that you have two seperate collections in Classification, which you want to appear as a single collection.
The IXmlSerialization route is pretty simple though. Just implement it as follows on your Classification class, and you'll get the desired result.
public class Classification : IXmlSerializable
{
public List<int> NewClassificationList { get; set; }
public List<string> OldClassificationList { get; set; }
public void WriteXml(System.Xml.XmlWriter writer)
{
foreach (var item in NewClassificationList)
{
writer.WriteElementString("NewClassification", item.ToString());
}
foreach (var item in OldClassificationList)
{
writer.WriteElementString("OldClassification", item.ToString());
}
}
public System.Xml.Schema.XmlSchema GetSchema()
{
throw new NotImplementedException();
}
public void ReadXml(System.Xml.XmlReader reader)
{
throw new NotImplementedException();
}
}
Added ReadXml implementation
ReadXml can be implemented as follows:
public void ReadXml(System.Xml.XmlReader reader)
{
var product = new Product();
product.Classification = new Classification { NewClassificationList = new List<int>(), ldClassificationList = new List<string>()};
reader.ReadStartElement("Classification");
while (reader.NodeType != System.Xml.XmlNodeType.EndElement)
{
switch (reader.Name)
{
case "NewClassification":
product.Classification.NewClassificationList.Add(reader.ReadElementContentAsInt());
break;
case "OldClassification":
product.Classification.OldClassificationList.Add(reader.ReadElementContentAsString());
break;
default:
throw new NotSupportedException("Unsupported node: " + reader.Name);
}
}
reader.ReadEndElement();
}

Related

ASP.NET Core API search parameters from path/route

I am porting a PHP/CI API that uses $params = $this->uri->uri_to_assoc() so that it can accept GET requests with many combinations, such as:
https://server/properties/search/beds/3/page/1/sort/price_desc
https://server/properties/search/page/2/lat/34.1/lon/-119.1
https://server/properties/search
etc
With lots of code like:
$page = 1;
if (!empty($params['page'])) {
$page = (int)$params['page'];
}
The two ASP.NET Core 2.1 techniques I've tried both seem like a kludge so I would appreciate any guidance on a better solution:
1) Conventional routing with catchall:
app.UseMvc(routes => {
routes.MapRoute(
name: "default",
template: "{controller=Properties}/{action=Search}/{*params}"
);
});
But now I have to parse the params string for the key/value pairs and am not able to take advantage of model binding.
2) Attribute routing:
[HttpGet("properties/search")]
[HttpGet("properties/search/beds/{beds}")]
[HttpGet("properties/search/beds/{beds}/page/{page}")]
[HttpGet("properties/search/page/{page}/beds/{beds}")]
public IActionResult Search(int beds, double lat, double lon, int page = 1, int limit = 10) {
}
Obviously putting every combination of allowed search parameters and values is tedious.
Changing the signature of these endpoints is not an option.
FromPath value provider
What you are wanting is to bind a complex model to part of the url path. Unfortunately, ASP.NET Core does not have a built-in FromPath binder. Fortunately, though, we can build our own.
Here is an example FromPathValueProvider in GitHub that has the following result:
Basically, it is binding domain.com/controller/action/key/value/key/value/key/value. This is different than what either the FromRoute or the FromQuery value providers do.
Use the FromPath value provider
Create a route like this:
routes.MapRoute(
name: "properties-search",
template: "{controller=Properties}/{action=Search}/{*path}"
);
Add the [FromPath] attribute to your action:
public IActionResult Search([FromPath]BedsEtCetera model)
{
return Json(model);
}
And magically it will bind the *path to a complex model:
public class BedsEtCetera
{
public int Beds { get; set; }
public int Page { get; set; }
public string Sort { get; set; }
}
Create the FromPath value provider
Create a new attribute based on FromRoute.
[AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Property,
AllowMultiple = false, Inherited = true)]
public class FromPath : Attribute, IBindingSourceMetadata, IModelNameProvider
{
/// <inheritdoc />
public BindingSource BindingSource => BindingSource.Custom;
/// <inheritdoc />
public string Name { get; set; }
}
Create a new IValueProviderFactory base on RouteValueProviderFactory.
public class PathValueProviderFactory : IValueProviderFactory
{
public Task CreateValueProviderAsync(ValueProviderFactoryContext context)
{
var provider = new PathValueProvider(
BindingSource.Custom,
context.ActionContext.RouteData.Values);
context.ValueProviders.Add(provider);
return Task.CompletedTask;
}
}
Create a new IValueProvider base on RouteValueProvider.
public class PathValueProvider : IValueProvider
{
public Dictionary<string, string> _values { get; }
public PathValueProvider(BindingSource bindingSource, RouteValueDictionary values)
{
if(!values.TryGetValue("path", out var path))
{
var msg = "Route value 'path' was not present in the route.";
throw new InvalidOperationException(msg);
}
_values = (path as string).ToDictionaryFromUriPath();
}
public bool ContainsPrefix(string prefix) => _values.ContainsKey(prefix);
public ValueProviderResult GetValue(string key)
{
key = key.ToLower(); // case insensitive model binding
if(!_values.TryGetValue(key, out var value)) {
return ValueProviderResult.None;
}
return new ValueProviderResult(value);
}
}
The PathValueProvider uses a ToDictionaryFromUriPath extension method.
public static class StringExtensions {
public static Dictionary<string, string> ToDictionaryFromUriPath(this string path) {
var parts = path.Split('/');
var dictionary = new Dictionary<string, string>();
for(var i = 0; i < parts.Length; i++)
{
if(i % 2 != 0) continue;
var key = parts[i].ToLower(); // case insensitive model binding
var value = parts[i + 1];
dictionary.Add(key, value);
}
return dictionary;
}
}
Wire things together in your Startup class.
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc()
.AddMvcOptions(options =>
options.ValueProviderFactories.Add(new PathValueProviderFactory()));
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
app.UseMvc(routes => {
routes.MapRoute(
name: "properties-search",
template: "{controller=Properties}/{action=Search}/{*path}"
);
});
}
}
Here is a working sample on GitHub.
Edit
My other answer is a better option.
General Idea
$params = $this->uri->uri_to_assoc() turns a URI into an associative array, which is basically a .NET Dictionary<TKey, TValue>. We can do something similar in ASP.NET Core. Lets say we have the following routes.
app.UseMvc(routes => {
routes.MapRoute(
name: "properties-search",
template: "{controller=Properties}/{action=Search}/{*params}"
);
});
Bind Uri Path to Dictionary
Action
public class PropertiesController : Controller
{
public IActionResult Search(string slug)
{
var dictionary = slug.ToDictionaryFromUriPath();
return Json(dictionary);
}
}
Extension Method
public static class UrlToAssocExtensions
{
public static Dictionary<string, string> ToDictionaryFromUriPath(this string path) {
var parts = path.Split('/');
var dictionary = new Dictionary<string, string>();
for(var i = 0; i < parts.Length; i++)
{
if(i % 2 != 0) continue;
var key = parts[i];
var value = parts[i + 1];
dictionary.Add(key, value);
}
return dictionary;
}
}
The result is an associative array based on the URI path.
{
"beds": "3",
"page": "1",
"sort": "price_desc"
}
But now I have to parse the params string for the key/value pairs and am not able to take advantage of model binding.
Bind Uri Path to Model
If you want model binding for this, then we need to go a step further.
Model
public class BedsEtCetera
{
public int Beds { get; set; }
public int Page { get; set; }
public string Sort { get; set; }
}
Action
public IActionResult Search(string slug)
{
BedsEtCetera model = slug.BindFromUriPath<BedsEtCetera>();
return Json(model);
}
Additional Extension Method
public static TResult BindFromUriPath<TResult>(this string path)
{
var dictionary = path.ToDictionaryFromUriPath();
var json = JsonConvert.SerializeObject(dictionary);
return JsonConvert.DeserializeObject<TResult>(json);
}
IMHO you are looking at this from the wrong perspective.
Create a model:
public class FiltersViewModel
{
public int Page { get; set; } = 0;
public int ItemsPerPage { get; set; } = 20;
public string SearchString { get; set; }
public string[] Platforms { get; set; }
}
API Endpoint:
[HttpGet]
public async Task<IActionResult> GetResults([FromRoute] ViewModels.FiltersViewModel filters)
{
// process the filters here
}
Result Object (dynamic)
public class ListViewModel
{
public object[] items;
public int totalCount = 0;
public int filteredCount = 0;
}

List <T> store large amounts of data , Not enough memory

public class ListKeywords
{
public int ID { set; get; }
public string Keyword { set; get; } //关键词
public string Language { set; get; } //语种
public int WordCount { set; get; } //单词数
public int WordLength { set; get; } // 字符数
public int Status { set; get; } //采集状态 0-未采集 1-采集成功 2-保存失败 3-保存成功 4-发布失败 5-发布成功
public bool Taken { set; get; }
public bool FTPStatus { set; get; }
public bool DBStatus { set; get; }
public string UrlName { set; get; }
public ListKeywords()
{
}
public ListKeywords(string keyword)
{
this.Keyword = keyword;
}
}
List<string> lines = new List<string>();
List<ListKeywords> keywordsList = new List<ListKeywords>();
using (StreamReader sr = File.OpenText(filePath))
{
string s = String.Empty;
while ((s = sr.ReadLine()) != null)
{
//lines.Add(s); //Operating normally
eywordsList.Add(new ListKeywords("some keywords")); // Operating normally
keywordsList.Add(new ListKeywords(s)); // it will be out of memeory
}
}
In text file, have 1,000,000 line data, if i use above code to load the large data to list< keywordsList >, it will raises an OutOfMemoryException, but if i load it to list< string >, it run normally. How to solved it ?
Instead of using a List maybe try using an IEnumerable w/ yield?
static IEnumerable<ListKeywords> Keywords()
{
using (StreamReader sr = File.OpenText(path))
{
string s = String.Empty;
while ((s = sr.ReadLine()) != null)
{
yield return new ListKeywords(s);
}
}
}
Note that Jon Skeet's C# in Depth offers a great explanation about this in Chapter 6. I imagine he also has some articles or posts on StackOverflow about this topic. As he points out, you want to be careful about modifying this method to pass in a StreamReader (or TextReader as is used in his example) as you would want to take ownership of the reader so it will be properly disposed of. Rather, you would want to pass in a Func<StreamReader> if you have such a need. Another interesting note he adds here - which I will point out because there are some edge cases where the reader will not actually be properly disposed of even if you don't allow the reader to be provided by the caller - it's possible for the caller to abuse the IEnumerable<ListKeywords> by doing something like Keywords().GetEnumerator() - this could result in a memory leak and could even potentially cause security issues if you have security-related code which relies on the using statement to clean up the resource.

Custom impromptuobject for json.net deserialization

I was playing around with impromptu interface over a jobject and ran into the following issue
https://code.google.com/p/impromptu-interface/issues/detail?id=17
The issue is marked as 'Won't fix' and in the comments the author says that it could be fixed by implementing a custom impromptuobject.
Anyone have a sample of such an implementation? Or know another solution to this problem?
So the problem is that JArray has GetEnumerator() defined as interface-only, which makes the method no longer duck callable by the DLR. So below I've overriden the trygetmember to check if the result is a JArray's and convert it to a JEnumerable that implements GetEnumerator() in a dlr invokable way.
public class NonRecursiveJArrayConversionDictionary : ImpromptuDictionary{
public override bool TryGetMember(GetMemberBinder binder, out object result)
{
if(base.TryGetMember(binder, out result)){
if(result is JArray){
result = ((JArray)result).AsJEnumerable();
}
return true;
}
result = null;
return false;
}
}
However, this will only work for json structures that don't have arrays more then one property deep. You'll either have modify the above to recursively check anytime anything is returned maybe with a proxy, or modify the dictionary indexer's set to check and convert when deserialized instead.
Update: Json.net verion >= 5.0.4.16101 and ImpromptuInterface >= 6.1.4 will work out of the box.
void Main()
{
ICustomer customer = Impromptu.ActLike(JObject.Parse(#"
{
Id: 1,
Name:'Test',
Location:'Somewhere',
Employees: [
{ Id:1, EmployerId:39421, Name:'Joe' },
{ Id:2, EmployerId:39421, Name:'Jane' },
]
}
"));
foreach(var employee in customer.Employees){
employee.Id.Dump();
employee.Name.Dump();
}
}
public interface ICustomer
{
int Id { get; set; }
string Name { get; set; }
string Location { get; set; }
IList<IEmployee> Employees { get; }
}
public interface IEmployee
{
int Id { get; set; }
int EmployerId { get; set; }
string Name { get; set; }
}

Nunit tests on Response.Cache.VaryByHeader

I am doing some Unit testing with NUnit and NSubstitute on a function that uses HttpResponse, I know you can't mock these objects so I have created interfaces to represent them and some of there properties.
I'm having trouble understanding how to create an interface for Response.Cache.VaryByHeader
// This is my HttpResponse interface
public interface IHttpResponse
{
Stream Filter { get ; set; }
IHttpCachePolicy Cache { get; set; }
void AppendHeader(string name, string value);
}
// concrete httresponse
public class HttpResponseProxy : IHttpResponse
{
private HttpResponse _httpResponse;
public Stream Filter {
get {
return _httpResponse.Filter ?? new MemoryStream();
}
set { _httpResponse.Filter = value; }
}
public IHttpCachePolicy Cache
{
get { return new HttpCachePolicyProxy(_httpResponse.Cache); }
set { }
}
public HttpResponseProxy(HttpResponse httpResponse)
{
if (httpResponse == null)
{
throw new ArgumentNullException("httpResponse");
}
_httpResponse = httpResponse;
_httpResponse.Filter = httpResponse.Filter;
}
public void AppendHeader(string name, string value)
{
_httpResponse.AppendHeader(name, value);
}
}
// HttpCachePolicy interface
public interface IHttpCachePolicy
{
IHttpCacheVaryByHeaders VaryByHeaders { get; set; }
}
// concrete HttpCachePolicy
public class HttpCachePolicyProxy : IHttpCachePolicy
{
private HttpCachePolicy _httpCachePolicy;
public HttpCachePolicyProxy(HttpCachePolicy httpCachePolicy)
{
_httpCachePolicy = httpCachePolicy;
}
public IHttpCacheVaryByHeaders VaryByHeaders
{
get { return new HttpCacheVaryByHeadersProxy(_httpCachePolicy.VaryByHeaders as HttpCacheVaryByHeaders); }
set { }
}
}
public interface IHttpCacheVaryByHeaders
{
IHttpCacheVaryByHeaders HttpCacheVaryByHeaders { get; set; }
}
public class HttpCacheVaryByHeadersProxy : IHttpCacheVaryByHeaders
{
private HttpCacheVaryByHeaders _httpCacheVaryByHeaders;
public HttpCacheVaryByHeadersProxy(HttpCacheVaryByHeaders httpCacheVaryByHeaders)
{
_httpCacheVaryByHeaders = httpCacheVaryByHeaders;
}
public IHttpCacheVaryByHeaders HttpCacheVaryByHeaders
{
get { return new HttpCacheVaryByHeadersProxy(_httpCacheVaryByHeaders); }
set { }
}
}
This is the function i am actually testing:
public static void CompressPage(IHttpRequestGetCompressionMode getCompressionMode, IHttpResponse httpResponse)
{
string supportedCompression = getCompressionMode.GetClientSupportedCompressionMode();
if (supportedCompression != HttpHeaderValues.NoCompression)
{
switch (supportedCompression)
{
case HttpHeaderValues.DeflateCompression:
httpResponse.Filter = new DeflateStream(httpResponse.Filter, CompressionMode.Compress);
break;
case HttpHeaderValues.GZipCompression:
httpResponse.Filter = new GZipStream(httpResponse.Filter, CompressionMode.Compress);
break;
}
httpResponse.AppendHeader(HttpHeaderValues.ContentEncodingHeader, supportedCompression);
// this line is where i have the problem
httpResponse.Cache.VaryByHeaders[HttpHeaderValues.AcceptEncodingHeader] = true;
}
}
I'm getting "cannot apply index to an expression of type IHttpCacheVaryByHeaders" errors.
I have the interface for the response and cache but how do I represent VaryByHeaders in an interface and then use it in a concrete class?
The error seems to suggest that IHttpCacheVaryByHeaders does not have an indexer declared (e.g. bool this[string header] { get; set; }), but rather than implementing these wrappers yourself, try the HttpResponseWrapper and other System.Web.Abstractions. This will should make testing this stuff a lot easier. :)

Create a log everytime When methods in an interface class are called

I want to update a log file(txt) everytime when methods in a an interface class are called?
Is there any way to do this other than writing code in every method to create log?
Here's my 30 mins. you'll have to implement the logging code somewhere so you have to create another abstraction for your code. thus an abstract class is needed. i think. this is very quick and dirty.
public interface IService<T>
{
List<T> GetAll();
bool Add(T obj);
}
then you'll need the abstract class where you'll need to implement your logging routine
public abstract class Service<T> : IService<T>
{
private void log()
{
/// TODO : do log routine here
}
public bool Add(T obj)
{
try
{
log();
return AddWithLogging(obj);
}
finally
{
log();
}
}
public List<T> GetAll()
{
try
{
log();
return GetAllWithLog();
}
finally
{
log();
}
}
protected abstract List<T> GetAllWithLog();
protected abstract bool AddWithLogging(T obj);
}
as for your concrete classes
public class EmployeeService : Service<Employee>
{
protected override List<Employee> GetAllWithLog()
{
return new List<Employee>() { new Employee() { Id = 0, Name = "test" } };
}
protected override bool AddWithLogging(Employee obj)
{
/// TODO : do add logic here
return true;
}
}
public class CompanyService : Service<Company>
{
protected override List<Company> GetAllWithLog()
{
return new List<Company>() { new Company() { Id = 0, Name = "test" } };
}
protected override bool AddWithLogging(Company obj)
{
/// TODO : do add logic here
return true;
}
}
public class Employee
{
public int Id {get;set;}
public string Name { get; set;}
}
public class Company
{
public int Id { get; set; }
public string Name { get; set; }
}
then on your implementation you can just..
static void Main(string[] args)
{
IService<Employee> employee = new EmployeeService();
List<Employee> employees = employee.GetAll();
foreach (var item in employees)
{
Console.WriteLine(item.Name);
}
IService<Company> company = new CompanyService();
List<Company> companies = company.GetAll();
foreach (var item in companies)
{
Console.WriteLine(item.Name);
}
Console.ReadLine();
}
hope this helps!
I think you would have to use Aspect Oriented Programming to achieve that. Read http://www.sharpcrafters.com/aop.net
I think you meant class (instead of interface)
Two options I can think of:
Implementing INotifyPropertyChanged which is in lines of writing code in every method
or
to adopt on of the AOP frameworks in the article http://www.codeproject.com/KB/cs/AOP_Frameworks_Rating.aspx if that is not a major leap

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