Doing sparql queries with JavaScript

 I tried this:

var $rdf = require('../rdflib.js');

var store = $rdf.graph()
var timeout = 5000 // 5000 ms timeout
var fetcher = new $rdf.Fetcher(store, timeout)
var url = 'http://bshambaugh.rww.io';
var LDP = $rdf.Namespace('http://www.w3.org/ns/ldp#');

fetcher.nowOrWhenFetched(url, function(ok, body, xhr) {
    if (!ok) {
        console.log("Oops, something happened and couldn't fetch data");
    } else {

   var me = $rdf.sym('http://bshambaugh.rww.io');
   var contains = LDP('contains')
   console.log(contains)

   var duh = $rdf.queryToSPARQL('SELECT *  FROM <http://bshambaugh.rww.io> WHERE { ?s ?p ?o . }');

   console.log("I fetched the data");
    }
})
                        
But I am getting issues like:

NamedNode { uri: 'http://www.w3.org/ns/ldp#contains' }
/home/brent/rdflib.js/dist/rdflib-node.js:6276
    for (var i = 0; i < query.vars.length; i++) {
                                  ^

TypeError: Cannot read property 'length' of undefined
    at getSelect (/home/brent/rdflib.js/dist/rdflib-node.js:6276:35)
    at getSPARQL (/home/brent/rdflib.js/dist/rdflib-node.js:6338:12)
    at Object.$rdf.queryToSPARQL (/home/brent/rdflib.js/dist/rdflib-node.js:6341:10)
    at /home/brent/rdflibexperiments/exp7.js:18:19
    at doneFetch (/home/brent/rdflib.js/dist/rdflib-node.js:9783:52)
    at /home/brent/rdflib.js/dist/rdflib-node.js:10479:20
    at xhr.handle (/home/brent/rdflib.js/dist/rdflib-node.js:9365:9)
    at .onreadystatechange (/home/brent/rdflib.js/dist/rdflib-node.js:10478:19)
    at dispatchEvent (/home/brent/rdflib.js/node_modules/xmlhttprequest/lib/XMLHttpRequest.js:591:25)
    at setState (/home/brent/rdflib.js/node_modules/xmlhttprequest/lib/XMLHttpRequest.js:610:14)

I am not really sure what I am supposed to call for rdflib.js for a sparql query. Are there any other javascript libraries that allow me to do sparql queries?

I found https://github.com/antoniogarrote/rdfstore-js .

Experiments with rdflib.js -- Sixth experiment

Create the file for the code:

vim exp6.js

Write the code:

var $rdf = require('../rdflib.js');

var store = $rdf.graph()
var timeout = 5000 // 5000 ms timeout
var fetcher = new $rdf.Fetcher(store, timeout)
var url = 'http://bshambaugh.rww.io';
var LDP = $rdf.Namespace('http://www.w3.org/ns/ldp#');

fetcher.nowOrWhenFetched(url, function(ok, body, xhr) {
    if (!ok) {
        console.log("Oops, something happened and couldn't fetch data");
    } else {

   var me = $rdf.sym('http://bshambaugh.rww.io');
   var contains = LDP('contains')
   console.log(contains)
   var friend = store.each(me, contains, undefined)
     // Any one person
        // do something with the data in the store (see below)
   for (var i=0; i<friend.length;i++) {
     console.log(friend[i])
   }
   console.log("I fetched the data");
    }
})
 

Run the code:

node exp6.js 

To get the results:

NamedNode { uri: 'http://www.w3.org/ns/ldp#contains' }
NamedNode { uri: 'http://bshambaugh.rww.io/.acl' }
NamedNode { uri: 'http://bshambaugh.rww.io/profile/' }
NamedNode { uri: 'http://bshambaugh.rww.io/storage/' }
I fetched the data

Comments about using rdflib.js to backup and migrate ldp server content

I would like to use rdflib.js to recursively create a backup of a linked data platform server.

 - I managed to get the child containers with the sixth experiment with rdflib.js
- I need to also find any contained RDF files (some other term in the ldp vocab.)
 - I need to also pull all the content for each ldp container)

- Then i need to do http requests to ldp server of my choice.
- and rewrite the ldp server uris appropriately (move from one content to another)

Getting started with rdflib.js -- Second experiment

Create a new file in the rdflibexperiments directory:

vim exp2.js

Add the contents:

var $rdf = require('../rdflib.js');

var uri = 'http://bshambaugh.rww.io/profile/card'
var body = '<a> <b> <c> .'
var mimeType = 'text/turtle'
var store = $rdf.graph()

try {
    $rdf.parse(body, store, uri, mimeType)
} catch (err) {
    console.log(err)
}

console.log(store);

Run the contents:

first in vim: wq!

second from the prompt: node exp2.js

To get the results:

var $rdf = require('../rdflib.js');

var uri = 'http://bshambaugh.rww.io/profile/card'
var body = '<a> <b> <c> .'
var mimeType = 'text/turtle'
var store = $rdf.graph()

try {
    $rdf.parse(body, store, uri, mimeType)
} catch (err) {
    console.log(err)
}

console.log(store);

Getting started with rdflib.js -- my first experiment

I cloned the github repository with:

git clone https://github.com/linkeddata/rdflib.js.git

then I followed the following steps:

cd rdflib.js

sudo su

npm install

make all

npm install -g jquery

npm install -g xmlhttprequest

I was inspired by the instructions at:

https://github.com/linkeddata/rdflib.js/

In separate directory at the same level of hierarchy on the directory tree I created a directory with the name "rdflibexperiments":

cd ..

mkdir rdflibexperiments

cd rdflibexperiments

Then I created a file called "exp1.js":

vim exp1.js

With the contents:

var $rdf = require('../rdflib.js');

var FOAF = $rdf.Namespace("http://xmlns.com/foaf/0.1/");

var foafKnows = FOAF('knows');

console.log(foafKnows);
 
Running this with the command

node exp1.js

gave

NamedNode { uri: 'http://xmlns.com/foaf/0.1/knows' }


The contents of the file was inspired by: 

https://github.com/solid/solid-tutorial-rdflib.js

with a friendly reminder from:

https://github.com/okcoders/ok-coders-summer-2014/blob/master/10-node/10-examples/calculator.js

wget and curl on bshambaugh.rww.io

Using curl pulls in the parent container:

curl -i -H "Accept: text/turtle" http://bshambaugh.rww.io

HTTP/1.1 200 OK
Date: Tue, 31 May 2016 01:49:38 GMT
Server: Apache/2.2.22 (Ubuntu)
X-Powered-By: PHP/5.3.10-1ubuntu3.22
Set-Cookie: SID=a0kehvcpo0pctkrlijd1t2fsb0; expires=Sun, 30-May-2021 01:49:38 GMT; path=/; domain=.rww.io
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: max-age=0
Pragma: no-cache
User: dns:107.196.158.16
Set-Cookie: showMetaFiles=deleted; expires=Thu, 01-Jan-1970 00:00:01 GMT
Link: <http://bshambaugh.rww.io/.acl>; rel=acl
MS-Author-Via: DAV, SPARQL
Allow: GET, PUT, POST, OPTIONS, HEAD, MKCOL, DELETE, PATCH
Accept-Patch: application/json, application/sparql-update
Accept-Post: text/turtle;charset=utf-8,text/n3;charset=utf-8,text/nt;charset=utf-8,text/css;charset=utf-8,text/html;charset=utf-8,text/javascript;charset=utf-8,text/plain;charset=utf-8,application/rdf+xml;charset=utf-8,application/json;charset=utf-8,multipart/form-data,image/jpeg,image/jpeg,image/png,image/gif,font/otf
Vary: Accept,Origin,If-Modified-Since,If-None-Match
Link: <http://www.w3.org/ns/ldp#BasicContainer>; rel="type"
Link: <http://www.w3.org/ns/ldp#Resource>; rel="type"
Link: <http://bshambaugh.rww.io/.meta>; rel=meta
Link: <http://bshambaugh.rww.io/?p=1>; rel='first'
Link: <http://bshambaugh.rww.io/?p=1>; rel='last'
ETag: "c6d5ed3581b8c61ff70775a7e43a3cb8"
Last-Modified: Tue, 07 Oct 2014 03:06:33 GMT
Updates-Via: ws://bshambaugh.rww.io:81
Triples: 17
Content-Length: 891
Content-Type: text/turtle

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

<>
    a <http://www.w3.org/ns/ldp#BasicContainer>, <http://www.w3.org/ns/ldp#Container>, <http://www.w3.org/ns/posix/stat#Directory> ;
    <http://www.w3.org/ns/ldp#contains> <.acl>, <profile/>, <storage/> ;
    <http://www.w3.org/ns/posix/stat#mtime> 1412651193 ;
    <http://www.w3.org/ns/posix/stat#size> 4096 .

<.acl>
    a <http://www.w3.org/2000/01/rdf-schema#Resource> ;
    <http://www.w3.org/ns/posix/stat#mtime> 1412651193 ;
    <http://www.w3.org/ns/posix/stat#size> 577 .

<profile/>
    a <http://www.w3.org/ns/posix/stat#Directory> ;
    <http://www.w3.org/ns/posix/stat#mtime> 1412651156 ;
    <http://www.w3.org/ns/posix/stat#size> 4096 .

<storage/>
    a <http://www.w3.org/ns/posix/stat#Directory> ;
    <http://www.w3.org/ns/posix/stat#mtime> 1422986228 ;
    <http://www.w3.org/ns/posix/stat#size> 4096 .

But what about recursively pulling in child containers? A discussion on the marmotta users list tells me this is not supported by the Linked Data Platform standard.
 https://lists.apache.org/thread.html/Zbr0lhfsuf2z183 
In any case,, I tried this with wget in the same way I would target a normal web server. It does not appear to behave the same way.


wget -mkq -np -nH -D bshambaugh.rww.io http://bshambaugh.rww.io

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

<>
    a <http://www.w3.org/ns/ldp#BasicContainer>, <http://www.w3.org/ns/ldp#Container>, <http://www.w3.org/ns/posix/stat#Directory> ;
    <http://www.w3.org/ns/ldp#contains> <.acl>, <profile/>, <storage/> ;
    <http://www.w3.org/ns/posix/stat#mtime> 1412651193 ;
    <http://www.w3.org/ns/posix/stat#size> 4096 .

<.acl>
    a <http://www.w3.org/2000/01/rdf-schema#Resource> ;
    <http://www.w3.org/ns/posix/stat#mtime> 1412651193 ;
    <http://www.w3.org/ns/posix/stat#size> 577 .

<profile/>
    a <http://www.w3.org/ns/posix/stat#Directory> ;
    <http://www.w3.org/ns/posix/stat#mtime> 1412651156 ;
    <http://www.w3.org/ns/posix/stat#size> 4096 .

<storage/>
    a <http://www.w3.org/ns/posix/stat#Directory> ;
    <http://www.w3.org/ns/posix/stat#mtime> 1422986228 ;
    <http://www.w3.org/ns/posix/stat#size> 4096 .