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How to Disable Attachments to List Items in SharePoint Online Using REST API

Introduction

SharePoint 2013 introduces a Representational State Transfer (REST) service that is comparable to the existing SharePoint client object models. This allows the developers to interact remotely with SharePoint data by using any technology that supports REST web requests. This means that developers can perform Create, Read, Update and Delete (CRUD) operations from their apps for SharePoint, solutions and client applications, using REST web technologies and standard Open Data Protocol (OData) syntax.

I have a custom list named “Custom List”. You will see how to disable attachments to list items in the custom list. (Navigate to the list. Click on the List tab in the ribbon interface. Click on List Settings. Click on Advanced Settings that is available under General Settings.)

In this article you will see the following:

  • Create an app using the NAPA Tool in SharePoint 2013 Online.
  • Cross-Domain Requests.
  • Disable attachments to list items using the REST API.

Endpoint URI

https://c986.sharepoint.com/_api/web/lists/getbytitle('listName')

Note: If you are making cross-domain requests then you need to add SP.AppContextSite(@target) and ?@target='<host web url>' to the endpoint URI.

Properties

The following properties need to be used in a REST request to disable attachments to list items.

  1. IF-MATCH header: It is required in POST requests for a MERGE operation. Description: Provides a way to verify that the object being changed has not been changed since it was last retrieved. Or, lets you specify to overwrite any changes, as shown in the following example: "IF-MATCH":"*".
  2. X-HTTP-Method header: It is required in POST requests for MERGE operations. Description: Used to specify that the request performs a MERGE operation. Example: "X-HTTP-Method":"MERGE".

MERGE Operation

MERGE operations are used to update existing SharePoint objects.

Use the following procedure to create an app using the NAPA Tool:

  1. Navigate to the SharePoint 2013 Online site.
  2. Click on Site Contents in the quick launch bar.
  3. Click on “Napa” Office 365 Development Tools.


     
  4. Click on Add New Project.


     
  5. Select App for SharePoint, enter the Project name and then click on Create.

Permissions

Ensure appropriate permission is provided to access the content. Click on the Properties button, and then click on Permissions. Set the required permission to access the content.

Default.aspx

Replace the contents of default.aspx with the following:

<%-- The markup and script in the following Content element will be placed in the <head>of the page --%>
<asp:Content ContentPlaceHolderID="PlaceHolderAdditionalPageHead" runat="server">
<script type="text/javascript" src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.9.1.min.js"></script>
<script type="text/javascript" src="/_layouts/15/sp.runtime.js"></script>
<script type="text/javascript" src="/_layouts/15/sp.js"></script>
<!-- Add your CSS styles to the following file -->
<link rel="Stylesheet" type="text/css" href="../Content/App.css" />
<!-- Add your JavaScript to the following file -->
<script type="text/javascript" src="../Scripts/App.js"></script>
</asp:Content>
<%-- The markup in the following Content element will be placed in the TitleArea of the page --%>
<asp:Content ContentPlaceHolderID="PlaceHolderPageTitleInTitleArea" runat="server">Page Title</asp:Content>
<%-- The markup and script in the following Content element will be placed in the <body>of the page --%>
<asp:Content ContentPlaceHolderID="PlaceHolderPageTitleInTitleArea" runat="server">REST API Examples</asp:Content>
<%-- The markup and script in the following Content element will be placed in the <body>of the page --%>
<asp:Content ContentPlaceHolderID="PlaceHolderMain" runat="server">
    <div>
        <p>
            <b>Disable attachments to list items</b>
            <br />
            <input type="text" value="List Name Here" id="listnametext" />
            <button id="disableattachmentsbutton">Disable Attachments</button>
        </p>
    </div>
</asp:Content>

App.js

Replace the contents ofApp.js with the following:

'use strict';
var hostweburl;
var appweburl;
// Load the required SharePoint libraries.
$(document).ready(function () {
    //Get the URI decoded URLs.
    hostweburl = decodeURIComponent(
    getQueryStringParameter("SPHostUrl"));
    appweburl = decodeURIComponent(
    getQueryStringParameter("SPAppWebUrl"));
    //Assign events to buttons
    $("#disableattachmentsbutton").click(function (event) {
        disableAttachments();
        event.preventDefault();
    });
    // Resources are in URLs in the form:
    // web_url/_layouts/15/resource
    var scriptbase = hostweburl + "/_layouts/15/";
    // Load the js file and continue to load the page.
    // SP.RequestExecutor.js to make cross-domain requests
    $.getScript(scriptbase + "SP.RequestExecutor.js");
});
// Utilities
// Retrieve a query string value.
// For production purposes you may want to use a library to handle the query string.
function getQueryStringParameter(paramToRetrieve) {
    var params = document.URL.split("?")[1].split("&");
    for (var i = 0; i < params.length; i = i + 1) {
        var singleParam = params[i].split("=");
        if (singleParam[0] == paramToRetrieve) return singleParam[1];
    }
}
// Disable Attachments to list items
function disableAttachments() {
    var listnametext = document.getElementById("listnametext").value;
    var executor;
    // Initialize the RequestExecutor with the app web URL.
    executor = new SP.RequestExecutor(appweburl);
    executor.executeAsync({
        url: appweburl + "/_api/SP.AppContextSite(@target)/web/lists/getbytitle('" + listnametext + "')?@target='" + hostweburl + "'",
        method: "POST",
        body: "{ '__metadata': { 'type': 'SP.List' }, 'EnableAttachments': false}",
        headers: {
            "IF-MATCH": "*",
            "X-HTTP-Method": "MERGE",
            "content-type": "application/json;odata=verbose"
        },
        success: disableAttachmentsSuccessHandler,
        error: disableAttachmentsErrorHandler
    });
}
// Success Handler
function disableAttachmentsSuccessHandler(data) {
    alert("Attachments to list item is disabled successfully")
}
// Error Handler
function disableAttachmentsErrorHandler(data, errorCode, errorMessage) {
    alert("Could not disable attachments: " + errorMessage);
}

Deploy the App

  1. Click on Run Project.


     
  2. The app will be packaged, deployed and launched.


     
  3. Click on “Click here to launch your app in a new window”.


     
  4. Click on Trust it.


     
  5. Enter the list name and then click on the Disable Attachments button.


     
  6. Attachments to list items are disabled successfully.

Summary

Thus in this article you saw how to disable attachments to list items using the REST API in SharePoint 2013 Online.


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