Post reply on SharePoint online discussion board using REST API - rest

Question

I am trying to post reply on a particular discussion of SharePoint online discussion board through REST API but unable to do it. I don't want to use SP.utilities as this REST API will be called from Android App.
Below is the code which I am implementing:
$.ajax({
url:"../_api/web/Lists/getbytitle(listname)/items?$filter=ParentItemID eq 40",
type: "POST",
contentType: "application/json;odata=verbose",
data: JSON.stringify(itemProperties),
headers: {
"Accept": "application/json;odata=verbose",
"X-RequestDigest": $("#__REQUESTDIGEST").val(),
"IF-MATCH": "*"
},
success: function (data) {
alert("Successfully posted!!");
},
error: function (error) {
alert("error");
console.log(JSON.stringify(error));
}
});
Instead of creating reply inside discussion, it is creating a new discussion item.
Any help will be highly appreciated.

Answer 1

For creating a message item (reply) in Discussion Board the following properties needs to be specified:
FileSystemObjectType for a message items needs to be set to 0
ContentTypeId- content type Id of message item
ParentItemID - discussion item (container for messages) id
Regarding ParentItemID property
ParentItemID property could not be specified via message payload since it is a read only property, it means the following query for creating a message item fails:
Url /_api/web/lists/getbytitle('Discussions')/items
Method POST
Data {
'__metadata': { "type": "SP.Data.DiscussionsListItem" },
'Body': "Message text goes here",
'FileSystemObjectType': 0,
'ContentTypeId': '<MessageContentTypeId>',
'ParentItemID': <DiscussionItemId>
}
Solution
The following example demonstrates how to to create a message (reply) in Discussion Board via SharePoint REST API.
For creating a message under a discussion item (folder) the following
approach is used: once message item is created, it's getting moved
under a discussion item
var listTitle = "Discussions"; //Discussions Board title
var webUrl = _spPageContextInfo.webAbsoluteUrl;
var messagePayload = {
'__metadata': { "type": "SP.Data.DiscussionsListItem" }, //set DiscussionBoard entity type name
'Body': "Message text goes here", //message Body
'FileSystemObjectType': 0, //set to 0 to make sure Message Item is created
'ContentTypeId': '0x0107008822E9328717EB48B3B665EE2266388E', //set Message content type
'ParentItemID': 123 //set Discussion item (topic) Id
};
createNewDiscussionReply(webUrl,listTitle,messagePayload)
.done(function(item)
{
console.log('Message(reply) has been sent');
})
.fail(function(error){
console.log(JSON.stringify(error));
});
where
function executeJson(options)
{
var headers = options.headers || {};
var method = options.method || "GET";
headers["Accept"] = "application/json;odata=verbose";
if(options.method == "POST") {
headers["X-RequestDigest"] = $("#__REQUESTDIGEST").val();
}
var ajaxOptions =
{
url: options.url,
type: method,
contentType: "application/json;odata=verbose",
headers: headers
};
if("data" in options) {
ajaxOptions.data = JSON.stringify(options.data);
}
return $.ajax(ajaxOptions);
}
function createListItem(webUrl,listTitle,payload){
var url = webUrl + "/_api/web/lists/getbytitle('" + listTitle + "')/items";
return executeJson({
"url" :url,
"method": 'POST',
"data": payload
});
}
function moveListItem(webUrl,listTitle,itemId,folderUrl){
var url = webUrl + "/_api/web/lists/getbytitle('" + listTitle + "')/getItemById(" + itemId + ")?$select=FileDirRef,FileRef";
return executeJson({
"url" :url
})
.then(function(result){
var fileUrl = result.d.FileRef;
var fileDirRef = result.d.FileDirRef;
var moveFileUrl = fileUrl.replace(fileDirRef,folderUrl);
var url = webUrl + "/_api/web/getfilebyserverrelativeurl('" + fileUrl + "')/moveto(newurl='" + moveFileUrl + "',flags=1)";
return executeJson({
"url" :url,
"method": 'POST'
});
});
}
function getParentTopic(webUrl,listTitle,itemId){
var url = webUrl + "/_api/web/lists/getbytitle('" + listTitle + "')/getItemById(" + itemId + ")/Folder";
return executeJson({
"url" :url,
});
}
function createNewDiscussionReply(webUrl,listTitle, messagePayload){
var topicUrl = null;
return getParentTopic(webUrl,listTitle,messagePayload.ParentItemID)
.then(function(result){
topicUrl = result.d.ServerRelativeUrl;
return createListItem(webUrl,listTitle,messagePayload);
})
.then(function(result){
var itemId = result.d.Id;
return moveListItem(webUrl,listTitle,itemId,topicUrl);
});
}