Salesforce Chatter Attaching Files to SObject

There are different ways you can use salesforce to attach a file to an SObject using Chatter.

• Apex Code
• Chatter REST Api

    public static void createAttachmentFeed(List<Attachment> attachments){
      for (Attachment attachment : attachments){
        // ContentVersion is how you upload a file!
       ContentVersion version = new ContentVersion();
       version.Title=attachment.Name;
       version.PathOnClient = '\\' + attachment.Name;
       version.VersionData = attachment.Body;
       version.NetWorkId = brightPlanWebCustomSettings.Community_Id__c;
       insert version;

       // After you insert the ContentVersion object, a base 'ContentDocument' is established
       // The ID of the ContentDocument is what you need to attach the file to the Chatter post.
       version = [SELECT ID,ContentDocumentId FROM ContentVersion WHERE ID=:version.id];

       // Form a basic post attached to our own feed.
       ConnectApi.FeedItemInput feedItem = new ConnectApi.FeedItemInput();
       feedItem.subjectId = attachment.ParentId; // This can also be an objectID to post the file to.

       // Now connect the feeditem to our already uploaded file.
       feedItem.capabilities = new ConnectAPI.FeedElementCapabilitiesInput();
       feedItem.capabilities.files = new ConnectAPI.FilesCapabilityInput();
       feedItem.capabilities.files.items = new List<ConnectAPI.FileIdInput>();
       ConnectAPI.FileIdInput attachFile = new ConnectAPI.FileIDInput();

       //**** Here is where we attach the specific file to the post!
       attachFile.id = version.contentDocumentid;
       feedItem.capabilities.files.items.add(attachFile);

       // Execute the posting
       ConnectApi.FeedElement feedElement = ConnectApi.ChatterFeeds.postFeedElement(brightPlanWebCustomSettings.Community_Id__c, feedItem);
      }
    }

Some limitations using this is using Blob for version.VersionData = attachment.Body; will run into Apex String length exceeds maximum: 6000000.

Chatter Rest API

POST https://cs43.salesforce.com/services/data/v35.0/connect/communities/0DB63000000003jGAA/chatter/feed-elements/batch

HEADER

Authorization         Bearer {sessionToken}

Content-Type          multipart/form-data; boundary=a7V4kRcFA8E79pivMuV2tukQ85cmNKeoEgJgq

Format is as follows:

{salesforceOrgUrl}/services/data/v35.0/connect/communities/{salesforceCommunityId}chatter/feed-elements/batch

The subjectId is the SObject Id to which you want to link the file, is this case we use our Case Id.

--a7V4kRcFA8E79pivMuV2tukQ85cmNKeoEgJgq
Content-Type: application/json; charset=UTF-8
Content-Disposition: form-data; name="json"
{
"inputs": [
{
"binaryPartNames": [
"file1"
],
"richInput": {
"subjectId": "50063000003YlSe",
"capabilities": {
"content": {
"title": "file1.pdf"
}
},
"feedElementType": "FeedItem"
}
},
{
"binaryPartNames": [
"file2"
],
"richInput": {
"subjectId": "50063000003YlSe",
"capabilities": {
"content": {
"title": "file2.pdf"
}
},
"feedElementType": "FeedItem"
}
}
]
}
--a7V4kRcFA8E79pivMuV2tukQ85cmNKeoEgJgq
Content-Type: application/octet-stream; charset=ISO-8859-1
Content-Disposition: form-data; name="file1"; filename="file1.pdf"

...contents of file1.pdf...

--a7V4kRcFA8E79pivMuV2tukQ85cmNKeoEgJgq
Content-Disposition: form-data; name="file2"; filename="file2.pdf"
Content-Type: application/octet-stream; charset=ISO-8859-1
...contents of file2.pdf...
--a7V4kRcFA8E79pivMuV2tukQ85cmNKeoEgJgq--

Benefits you can batch upload files without hitting an Apex limits.

Both the Chatter and Apex solutions can be used by Community Users to upload files.