Add Facebook attachment upload api

[ouadie-lahdioui]

Hello,

This PR add Facebook attachment upload API to allow us uploading an attachment that we may later send out to many users, without having to repeatedly upload the same data each time it is sent.

🍺 in honor of @jonchurch 🍺

Enjoy,

[benbrown]

Is this the same as #870?

[ouadie-lahdioui]

No it isn't, the aim of #870 is to allow to the user to send a local file, audio, video or an image instead of sending a cloud hosted files, for example if i want to send an image :

with Botkit today :

controller.hears(['doIt'], 'message_received', function(bot, message) {
    var image = {
        "attachment":{
            "type":"image",
            "payload":{
                "url": "http://CLOUD-HOSTED-SITE/images/image.png"
            }
        }
    };
    bot.reply(message, image);
});

To allow Facebbok render the images, we must provide a public link in payload.url, but what if i want to send an image from my local /User/Doc/images folder ?

With Botkit + #870 :

controller.hears(['doIt'], 'message_received', function(bot, message) {
    var image = {
        "attachment":{
            "type":"image",
            "payload":{
                "url": ""
            },
            filedata: FILE_FROM_LOCAL_FOLDER
        }
    };
    bot.reply(message, image);
});

In this way, FILE_FROM_LOCAL_FOLDER can be a file from my /User/Doc/images folder.

Furthermore, what if i want to upload an image that i can later send out to many users ? in this case Facebook Attachment Upload API is the answer, and with #899 Botkit will be able to upload (and just upload) files (audio, video, images ...) to send them later.

[benbrown]

hey @ouadie-lahdioui can you take out these actual keys?

[ouadie-lahdioui]

something is wrong with examples/facebook_bot.js, i will clean it

[ouadie-lahdioui]

Done.

[jonchurch]

👍🐙🍻