add JSON encoding of information from Welcome page

[daira]

Requested by Shu Lin on tahoe-dev. This should include the tubid, node public key, and information about any connected storage servers, introducer and helper.

[dawuud]

ok i've made some progress here: ​https://github.com/david415/tahoe-lafs/tree/2476.add_json_welcome_page.0

it works... output json with a list of summaries for connections to introducers and storage servers:

` {

"introducers": {

"statuses": [

"Connected to tcp:127.0.0.1:33791 via tcp"

]

}, "servers": {

"statuses": [

"Connected to tcp:127.0.0.1:41421 via tcp"

]

}

} `

i can change the format but i did it like this because it was easiest. For each storage server and introducer we get a ConnectionStatus object which contains a summary string. If we want the data in a different format then I can make some changes.

[cypher]

This will be tremendously useful for developers who want to use of this information without having parse out the welcome page's HTML -- thanks! ;)

How difficult or time-consuming would it be to insert the remainder of the information from the storage servers table? I'm thinking of something like this for the "servers" section (using example data from the Public Test Grid):

{
    "servers" :{
        "v0-5sprlixushufwhh5fqnxsitmk2ys4nmusgadjgrtjfb3lk4s57ia": {
            "available_space": null,
            "connection_status": "Reconnecting in 536 seconds (last attempt 1418s ago)",
            "nickname": "Sasquatch",
            "last_received_data": null,
            "version": "tahoe-lafs/1.12.0"
        },
        "v0-oii62uew7mnhkabtzkpxti62qyqk4smnoy6czz7waqdlorpqk4qa": {
            "available_space": "739292720660",
            "connection_status": "Connected to tcp:194.88.245.210:42998 via tcp",
            "nickname": "WXD",
            "last_received_data": "2017-01-13 10:59:48",
            "version": "tahoe-lafs/1.11.0"
        },
        "v0-x4zq6fof6eyr2y2ylhy6lc5vsnxrlh25mbnmm6xnodyrk4fejb3q": {
            "available_space": "13819057274",
            "connection_status": "Reconnecting in 536 seconds (last attempt 1418s ago)",
            "nickname": "drixter",
            "last_received_data": "2017-01-13 10:59:47",
            "version": "tahoe-lafs/1.11.0"
        }
    }
}

[dawuud]

OK I've provided the additional requested structure and information... See if you like it, let me know if you have additional things you want to add.

[dawuud]

​https://github.com/tahoe-lafs/tahoe-lafs/pull/399

[Brian Warner <warner@…>]

In d018a07/trunk:

Merge PR430: add JSON welcome page

closes ticket:2476