JSON support in REST data service – Part II

Post the User Post with a JSON Template

In the previous part we used the REST data service to fetch a set of users in JSON format and present them in a list view and as a JSON text string. In this example we call the same service to get related user information and send a request to add new information. The fake online service we use returns a correct JSON response but will not create anything in the database of the service. Smart Office 10.2.1.0.367 HF38 is required.

 

Mashup_REST_JSON_POST

First we define another data operation to create a user post by sending a JSON request,

<mashup:DataOperation Name="CreateUserPost">
    <mashup:DataParameter Key="REST.BaseAddress" Value="https://jsonplaceholder.typicode.com/posts" />
    <mashup:DataParameter Key="REST.InputJsonTemplate" Value="{StaticResource PostTemplate}" />
    <mashup:DataParameter Key="REST.AcceptHeader" Value="application/json" />
    <mashup:DataParameter Key="REST.HttpMethod" Value="POST" />
    <mashup:DataParameter Key="REST.InputType" Value="json" />
    <mashup:DataParameter Key="REST.OutputType" Value="application/json" />
</mashup:DataOperation>

and we also add a Send button containing an event that collects required values and trigger the CreateUserPost operation.

<Button DockPanel.Dock="Top" HorizontalAlignment="Right" Margin="5" Content="Send">
   <Button.CommandParameter>
            <mashup:Events>
                 <mashup:Event TargetName="PostComment" SourceEventName="Click" TargetEventName="CreateUserPost">
                 <mashup:Parameter TargetKey="title" Value="{Binding ElementName=PostTitle, Path=Text}" />
                 <mashup:Parameter TargetKey="body" Value="{Binding ElementName=PostBody, Path=Text}" />
                 <mashup:Parameter TargetKey="userId" Value="{Binding ElementName=UsersList, Path=CurrentItem[id]}" />
             </mashup:Event>
         </mashup:Events>
    </Button.CommandParameter>
</Button>

A press of the Send button collects the parameters and creates a JSON parameter body to be part of the server request. The body will look like this.

{
   "title": "test",
   "body": "test",
   "userId": "2",
}

Notice that the userId is a string but for the service we call, assume it must be a numeric value. Imagine that we need to customize the body for the service request since the default one will not do the trick.

Let’s create a template for the body that will result in the following JSON.

{
   "title": "test",
   "body": "test",
   "userId": 2,
}

First we add the template as a resource in the Mashup code within a CDATA block.

<Grid.Resources>   
      <x:String x:Key="PostTemplate"><![CDATA[      
               { 
                 "title": "{title}",
                 "body": "{body}",
                 "userId": {userId}
               }
            ]]></x:String>
   </Grid.Resources>

Next step is to add a template reference in the data operation declaration using the InputJsonTemplate parameter .

<mashup:DataOperation Name="CreateUserPost">
    <mashup:DataParameter Key="REST.BaseAddress" Value="https://jsonplaceholder.typicode.com/posts" />
    <mashup:DataParameter Key="REST.InputJsonTemplate" Value="{StaticResource PostTemplate}" />

Done! This is all that is needed to customize the server request body instead of getting the default one generated.

The full Mashup code if you would like to try it out.

<Grid Margin="15,10,15,15" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:ui="clr-namespace:Mango.UI.Controls;assembly=Mango.UI" xmlns:mashup="clr-namespace:Mango.UI.Services.Mashup;assembly=Mango.UI" xmlns:m3="clr-namespace:MForms.Mashup;assembly=MForms" xmlns:sys="clr-namespace:System;assembly=mscorlib">
	<Grid.RowDefinitions>
		<RowDefinition Height="1*" />
		<RowDefinition Height="10" />
		<RowDefinition Height="1*" />
		<RowDefinition Height="Auto" />
	</Grid.RowDefinitions>
	<Grid.ColumnDefinitions>
		<ColumnDefinition Width="1*" />
		<ColumnDefinition Width="10" />
		<ColumnDefinition Width="1*" />
	</Grid.ColumnDefinitions>
	<Grid.Resources>
		<x:String x:Key="PostTemplate"><![CDATA[		
					{ 
					  "title": "{title}",
					  "body": "{body}",
					  "userId": {userId}
					}
				]]></x:String>
	</Grid.Resources>
	<mashup:DataListPanel Name="UsersList" Grid.Column="0" Grid.Row="0" Grid.RowSpan="3">
		<mashup:DataListPanel.DataService>
			<mashup:DataService Type="REST">
				<mashup:DataService.Operations>
					<mashup:DataOperation Name="List">
						<mashup:DataParameter Key="REST.BaseAddress" Value="https://jsonplaceholder.typicode.com/users/" />
						<mashup:DataParameter Key="REST.OutputType" Value="DataItem" />
						<mashup:DataParameter Key="REST.AcceptHeader" Value="application/json" />
					</mashup:DataOperation>
				</mashup:DataService.Operations>
			</mashup:DataService>
		</mashup:DataListPanel.DataService>
		<mashup:DataListPanel.Events>
			<mashup:Events>
				<mashup:Event SourceEventName="Startup" TargetEventName="List" />
			</mashup:Events>
		</mashup:DataListPanel.Events>
		<ListView Name="ListViewCompany" ItemsSource="{Binding Items}" Style="{DynamicResource styleListView}" ItemContainerStyle="{DynamicResource styleListViewItem}">
			<ListView.View>
				<GridView ColumnHeaderContainerStyle="{DynamicResource styleGridViewColumnHeader}">
					<GridView.Columns>
						<GridViewColumn Header="Company" DisplayMemberBinding="{Binding [company].[name]}" />
						<GridViewColumn Header="City" DisplayMemberBinding="{Binding [address].[city]}" />
						<GridViewColumn Header="Name" DisplayMemberBinding="{Binding [name]}" />
						<GridViewColumn Header="Email" DisplayMemberBinding="{Binding [email]}" />
						<GridViewColumn Header="Longitude" DisplayMemberBinding="{Binding [address].[geo].[lng]}" />
						<GridViewColumn Header="Longitude" DisplayMemberBinding="{Binding [address].[geo].[lng]}" />
					</GridView.Columns>
				</GridView>
			</ListView.View>
		</ListView>
	</mashup:DataListPanel>
	<mashup:DataPanel Grid.Row="0" Grid.Column="2" Grid.RowSpan="3" Name="PostComment">
		<mashup:DataPanel.DataService>
			<mashup:DataService Type="REST">
				<mashup:DataService.Operations>
					<mashup:DataOperation Name="ListUserPost">
						<mashup:DataParameter Key="REST.BaseAddress" Value="https://jsonplaceholder.typicode.com/posts/?userid={userId}" />
						<mashup:DataParameter Key="REST.AcceptHeader" Value="application/json" />
					</mashup:DataOperation>
					<mashup:DataOperation Name="CreateUserPost">
						<mashup:DataParameter Key="REST.BaseAddress" Value="https://jsonplaceholder.typicode.com/posts" />
						<mashup:DataParameter Key="REST.InputJsonTemplate" Value="{StaticResource PostTemplate}" />
						<mashup:DataParameter Key="REST.AcceptHeader" Value="application/json" />
						<mashup:DataParameter Key="REST.HttpMethod" Value="POST" />
						<mashup:DataParameter Key="REST.InputType" Value="json" />
						<mashup:DataParameter Key="REST.OutputType" Value="application/json" />
						<!-- Change to DataItem to use return data -->
					</mashup:DataOperation>
				</mashup:DataService.Operations>
			</mashup:DataService>
		</mashup:DataPanel.DataService>
		<mashup:DataPanel.Events>
			<mashup:Events>
				<mashup:Event SourceEventName="Startup" TargetEventName="List" />				
			</mashup:Events>
		</mashup:DataPanel.Events>
		<Grid Margin="10,0,10,0">
			<Grid.RowDefinitions>
				<RowDefinition Height="Auto" />
				<RowDefinition Height="10" />
				<RowDefinition Height="Auto" />
				<RowDefinition Height="10" />
				<RowDefinition Height="Auto" />
			</Grid.RowDefinitions>
			<DockPanel Grid.Row="0">
				<TextBlock DockPanel.Dock="Left" Text="Post a comment as" Margin="0,0,5,0" />
				<TextBlock DockPanel.Dock="Left" Text="{Binding ElementName=UsersList, Path=CurrentItem[name]}" />
			</DockPanel>
			<DockPanel Grid.Row="2">
				<TextBlock DockPanel.Dock="Top" Text="Title" Margin="5" />
				<TextBox DockPanel.Dock="Top" Name="PostTitle" Margin="5" />
				<TextBlock DockPanel.Dock="Top" Text="Content" Margin="5" />
				<TextBox DockPanel.Dock="Top" Name="PostBody" Margin="5" />
				<Button DockPanel.Dock="Top" HorizontalAlignment="Right" Margin="5" Content="Send">
					<Button.CommandParameter>
						<mashup:Events>
							<mashup:Event TargetName="PostComment" SourceEventName="Click" TargetEventName="CreateUserPost">
								<mashup:Parameter TargetKey="title" Value="{Binding ElementName=PostTitle, Path=Text}" />
								<mashup:Parameter TargetKey="body" Value="{Binding ElementName=PostBody, Path=Text}" />
								<mashup:Parameter TargetKey="userId" Value="{Binding ElementName=UsersList, Path=CurrentItem[id]}" />
							</mashup:Event>
						</mashup:Events>
					</Button.CommandParameter>
				</Button>
			</DockPanel>
			<DockPanel Grid.Row="4">
				<TextBlock DockPanel.Dock="Top" Text="Server Response:" Width="140" Margin="5" VerticalAlignment="Top" HorizontalAlignment="Left" />
				<TextBox Height="120" DockPanel.Dock="Top" Text="{Binding [json]}" Margin="5" HorizontalAlignment="Stretch" VerticalAlignment="Top" VerticalContentAlignment="Top" TextWrapping="Wrap" AcceptsReturn="True" />
			</DockPanel>
		</Grid>
	</mashup:DataPanel>
</Grid>

 

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