dotnetrdf-develop — Developer Discussion and Feature Request

Re: [dotNetRDF-develop] SPARQL Parameterized String

[Rob V. <ra...@ec...>]

Hi Alexander

 

For the purposes of standardisation the escaping is handled by the fact that
the TurtleWriterContext class already does all the escaping we need.  If you
look at the ToString() method you'll see if calls the FormatNode method of
its local instance of this class which outputs the Node as an appropriate
string with escapes as necessary.

 

It is not necessary to be quite as paranoid as the slides suggest since as
long as we format the value into valid Turtle syntax for the Node then it
will be perfectly safe in a SPARQL query.  For example if you were to use a
literal with a quote it would insert it as a long literal in the SPARQL
query e.g.

 

SparqlParameterizedString queryString = new SparqlParameterizedString();

queryString.QueryText = @"PREFIX : <http://example.org/>

SELECT * WHERE {?s :property @value}";

queryString.SetLiteral("value", "This string contains a \" quote
character");

 

Results in the following SPARQL string when ToString() is called:

 

PREFIX : <http://example.org>

SELECT * WHERE {?s :property """This string contains a " quote character"""}

 

Which is a valid long literal and doesn't allow stuff to be injected, even
if Unicode (\u and \U) escapes are used like the slides discuss this doesn't
matter since the value just remains encoded as part of the string and can't
be used to break out of the quotes and inject stuff into the query.

 

Rob

 

From: Alexander Sidorov [mailto:ale...@gm...] 
Sent: 26 February 2010 13:21
To: dot...@li...
Subject: Re: [dotNetRDF-develop] Dotnetrdf-develop Digest, Vol 3, Issue 3

 

Hi Rob,

In general I like the approach you have chosen. But I looked through the
sources and haven't found any escaping. What if the literal from your
example contains quotation? At the moment I can't tell what symbols exactly
should be escaped... but you can look at SqlCommand sources. Also there is
some information about it in the presentation (for example, slide 35).

Regards,
Alexander

2010/2/26 <dot...@li...>

Send Dotnetrdf-develop mailing list submissions to
       dot...@li...

To subscribe or unsubscribe via the World Wide Web, visit
       https://lists.sourceforge.net/lists/listinfo/dotnetrdf-develop
or, via email, send a message with subject or body 'help' to
       dot...@li...

You can reach the person managing the list at
       dot...@li...

When replying, please edit your Subject line so it is more specific
than "Re: Contents of Dotnetrdf-develop digest..."


Today's Topics:

  1. SPARQL escaping helper class (Alexander Sidorov)
  2. Re: SPARQL escaping helper class (Rob Vesse)


----------------------------------------------------------------------

Message: 1
Date: Fri, 26 Feb 2010 10:00:11 +0100
From: Alexander Sidorov <ale...@gm...>
Subject: [dotNetRDF-develop] SPARQL escaping helper class
To: dot...@li...
Message-ID:
       <828...@ma...>
Content-Type: text/plain; charset="iso-8859-1"

Hello!

I think it would be useful to have a helper class for escaping SPARQL
queries (look this:
http://www.slideshare.net/Morelab/sparqlrdqlsparul-injection).

Regards,
Alexander
-------------- next part --------------
An HTML attachment was scrubbed...

------------------------------

Message: 2
Date: Fri, 26 Feb 2010 12:00:42 -0000
From: "Rob Vesse" <ra...@ec...>
Subject: Re: [dotNetRDF-develop] SPARQL escaping helper class
To: "'dotNetRDF Developer Discussion and Feature Request'"
       <dot...@li...>
Cc: ale...@gm...
Message-ID:
 
<EMEW3|6a27e0494e3d986b456109309e7d7fffm1PC0p06rav08r|ecs.soton.ac.uk|004a01
cab6db$522b4160$f681c420$@soton.ac.uk>

Content-Type: text/plain; charset="us-ascii"

Hi Alexander



That is an excellent suggestion, I have added a SparqlParameterizedString
class as of revision 631.  It takes a base query string with parameters in
the ADO.Net style like so:



SparqlParameterizedString queryString = new
SparqlParameterizedString("SELECT * WHERE {?s a @type}");



Or you can initialise an empty string and then use the QueryText property to
get/set/append to the raw query text

Then there's a variety of methods for setting the parameters (SetLiteral,
SetUri and SetBlankNode) which insert values for the parameters e.g.



queryString.SetUri("type", new Uri("http://example.org/myType"));



The actual value of the query string is returned by the ToString() method,
so for the above example ToString() returns the following:



SELECT * WHERE {?s a <http://example.org/myType>}



If the user was to instead try to inject something by setting a string like
so this wouldn't work, they'd simply get back the entire thing enclosed in
the literal so they can't change the value of the original query.



queryString.SetLiteral("type", "<http://example.org/myType>  ; ?prop
?value");



Results in:



SELECT * WHERE {?s a "<http://example.org/myType> ; ?prop ?value"}



Take a look and let me know what you think of it - does it do everything you
need/want it to?



The class is also reusable in that if you set a parameter that has already
been set it just changes the value for that parameter so that next time you
call ToString() you get the query with the new parameter values inserted
i.e. you don't have to instantiate a new instance of the class if you want
to make a query multiple times and substitute in different values each time.



Thanks,

Rob



From: Alexander Sidorov [mailto:ale...@gm...]
Sent: 26 February 2010 09:00
To: dot...@li...
Subject: [dotNetRDF-develop] SPARQL escaping helper class



Hello!

I think it would be useful to have a helper class for escaping SPARQL
queries (look this:
http://www.slideshare.net/Morelab/sparqlrdqlsparul-injection).

Regards,
Alexander

-------------- next part --------------
An HTML attachment was scrubbed...

------------------------------

----------------------------------------------------------------------------
--
Download Intel&#174; Parallel Studio Eval
Try the new software tools for yourself. Speed compiling, find bugs
proactively, and fine-tune applications for parallel performance.
See why Intel Parallel Studio got high marks during beta.
http://p.sf.net/sfu/intel-sw-dev

------------------------------

_______________________________________________
Dotnetrdf-develop mailing list
Dot...@li...
https://lists.sourceforge.net/lists/listinfo/dotnetrdf-develop


End of Dotnetrdf-develop Digest, Vol 3, Issue 3
***********************************************

 

Re: [dotNetRDF-develop] Dotnetrdf-develop Digest, Vol 3, Issue 3

[Alexander S. <ale...@gm...>]

Hi Rob,

In general I like the approach you have chosen. But I looked through the
sources and haven't found any escaping. What if the literal from your
example contains quotation? At the moment I can't tell what symbols exactly
should be escaped... but you can look at SqlCommand sources. Also there is
some information about it in the presentation (for example, slide 35).

Regards,
Alexander

2010/2/26 <dot...@li...>

> Send Dotnetrdf-develop mailing list submissions to
>        dot...@li...
>
> To subscribe or unsubscribe via the World Wide Web, visit
>        https://lists.sourceforge.net/lists/listinfo/dotnetrdf-develop
> or, via email, send a message with subject or body 'help' to
>        dot...@li...
>
> You can reach the person managing the list at
>        dot...@li...
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Dotnetrdf-develop digest..."
>
>
> Today's Topics:
>
>   1. SPARQL escaping helper class (Alexander Sidorov)
>   2. Re: SPARQL escaping helper class (Rob Vesse)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 26 Feb 2010 10:00:11 +0100
> From: Alexander Sidorov <ale...@gm...>
> Subject: [dotNetRDF-develop] SPARQL escaping helper class
> To: dot...@li...
> Message-ID:
>        <828...@ma...>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hello!
>
> I think it would be useful to have a helper class for escaping SPARQL
> queries (look this:
> http://www.slideshare.net/Morelab/sparqlrdqlsparul-injection).
>
> Regards,
> Alexander
> -------------- next part --------------
> An HTML attachment was scrubbed...
>
> ------------------------------
>
> Message: 2
> Date: Fri, 26 Feb 2010 12:00:42 -0000
> From: "Rob Vesse" <ra...@ec...>
> Subject: Re: [dotNetRDF-develop] SPARQL escaping helper class
> To: "'dotNetRDF Developer Discussion and Feature Request'"
>        <dot...@li...>
> Cc: ale...@gm...
> Message-ID:
>        <EMEW3|6a27e0494e3d986b456109309e7d7fffm1PC0p06rav08r|
> ecs.soton.ac.uk|004a01cab6db$522b4160$f681c420$@soton.ac.uk>
>
> Content-Type: text/plain; charset="us-ascii"
>
> Hi Alexander
>
>
>
> That is an excellent suggestion, I have added a SparqlParameterizedString
> class as of revision 631.  It takes a base query string with parameters in
> the ADO.Net style like so:
>
>
>
> SparqlParameterizedString queryString = new
> SparqlParameterizedString("SELECT * WHERE {?s a @type}");
>
>
>
> Or you can initialise an empty string and then use the QueryText property
> to
> get/set/append to the raw query text
>
> Then there's a variety of methods for setting the parameters (SetLiteral,
> SetUri and SetBlankNode) which insert values for the parameters e.g.
>
>
>
> queryString.SetUri("type", new Uri("http://example.org/myType"));
>
>
>
> The actual value of the query string is returned by the ToString() method,
> so for the above example ToString() returns the following:
>
>
>
> SELECT * WHERE {?s a <http://example.org/myType>}
>
>
>
> If the user was to instead try to inject something by setting a string like
> so this wouldn't work, they'd simply get back the entire thing enclosed in
> the literal so they can't change the value of the original query.
>
>
>
> queryString.SetLiteral("type", "<http://example.org/myType>  ; ?prop
> ?value");
>
>
>
> Results in:
>
>
>
> SELECT * WHERE {?s a "<http://example.org/myType> ; ?prop ?value"}
>
>
>
> Take a look and let me know what you think of it - does it do everything
> you
> need/want it to?
>
>
>
> The class is also reusable in that if you set a parameter that has already
> been set it just changes the value for that parameter so that next time you
> call ToString() you get the query with the new parameter values inserted
> i.e. you don't have to instantiate a new instance of the class if you want
> to make a query multiple times and substitute in different values each
> time.
>
>
>
> Thanks,
>
> Rob
>
>
>
> From: Alexander Sidorov [mailto:ale...@gm...]
> Sent: 26 February 2010 09:00
> To: dot...@li...
> Subject: [dotNetRDF-develop] SPARQL escaping helper class
>
>
>
> Hello!
>
> I think it would be useful to have a helper class for escaping SPARQL
> queries (look this:
> http://www.slideshare.net/Morelab/sparqlrdqlsparul-injection).
>
> Regards,
> Alexander
>
> -------------- next part --------------
> An HTML attachment was scrubbed...
>
> ------------------------------
>
>
> ------------------------------------------------------------------------------
> Download Intel&#174; Parallel Studio Eval
> Try the new software tools for yourself. Speed compiling, find bugs
> proactively, and fine-tune applications for parallel performance.
> See why Intel Parallel Studio got high marks during beta.
> http://p.sf.net/sfu/intel-sw-dev
>
> ------------------------------
>
> _______________________________________________
> Dotnetrdf-develop mailing list
> Dot...@li...
> https://lists.sourceforge.net/lists/listinfo/dotnetrdf-develop
>
>
> End of Dotnetrdf-develop Digest, Vol 3, Issue 3
> ***********************************************
>

Re: [dotNetRDF-develop] SPARQL escaping helper class

[Rob V. <ra...@ec...>]

Hi Alexander

 

That is an excellent suggestion, I have added a SparqlParameterizedString
class as of revision 631.  It takes a base query string with parameters in
the ADO.Net style like so:

 

SparqlParameterizedString queryString = new
SparqlParameterizedString("SELECT * WHERE {?s a @type}");

 

Or you can initialise an empty string and then use the QueryText property to
get/set/append to the raw query text

Then there's a variety of methods for setting the parameters (SetLiteral,
SetUri and SetBlankNode) which insert values for the parameters e.g.

 

queryString.SetUri("type", new Uri("http://example.org/myType"));

 

The actual value of the query string is returned by the ToString() method,
so for the above example ToString() returns the following:

 

SELECT * WHERE {?s a <http://example.org/myType>}

 

If the user was to instead try to inject something by setting a string like
so this wouldn't work, they'd simply get back the entire thing enclosed in
the literal so they can't change the value of the original query.

 

queryString.SetLiteral("type", "<http://example.org/myType>  ; ?prop
?value");

 

Results in:

 

SELECT * WHERE {?s a "<http://example.org/myType> ; ?prop ?value"}

 

Take a look and let me know what you think of it - does it do everything you
need/want it to?

 

The class is also reusable in that if you set a parameter that has already
been set it just changes the value for that parameter so that next time you
call ToString() you get the query with the new parameter values inserted
i.e. you don't have to instantiate a new instance of the class if you want
to make a query multiple times and substitute in different values each time.

 

Thanks,

Rob

 

From: Alexander Sidorov [mailto:ale...@gm...] 
Sent: 26 February 2010 09:00
To: dot...@li...
Subject: [dotNetRDF-develop] SPARQL escaping helper class

 

Hello!

I think it would be useful to have a helper class for escaping SPARQL
queries (look this:
http://www.slideshare.net/Morelab/sparqlrdqlsparul-injection).

Regards,
Alexander

[dotNetRDF-develop] SPARQL escaping helper class

[Alexander S. <ale...@gm...>]

Hello!

I think it would be useful to have a helper class for escaping SPARQL
queries (look this:
http://www.slideshare.net/Morelab/sparqlrdqlsparul-injection).

Regards,
Alexander

Re: [dotNetRDF-develop] [dotNetRDF-bugs] SparqlResult by index

[Rob V. <rv...@do...>]

Hi Alexander

 

I have added an additional property as of revision 626 which allows you to
get elements by index plus a Count property that lets you find out how many
values a result contains.

 

SPARQL queries in  general don't necessarily guarantee any order for
Variables although if you've specified specific variables in the SELECT
clause they should in theory be returned in order.  From an API standpoint
it's more convenient to have the values in a dictionary associated with
their variable names.

 

Thanks,

Rob Vesse

 

From: Alexander Sidorov [mailto:ale...@gm...] 
Sent: 22 February 2010 10:07
To: dotNetRDF Bug Report tracking and resolution
Subject: [dotNetRDF-bugs] SparqlResult by index

 

Hello!

SparqlResult doesn't support choosing element by index. As I understand the
reason for that is using Dictionary as results storage (and dictionary
doesn't guarantee any order). Replacing Dictionary by List could solve this
problem (but maybe bring some new :) ).

I think such a functionality would be useful (and I think performance would
be better).

Regards,
Alexander

Re: [dotNetRDF-develop] [dotNetRDF-bugs] Bugs, problems, ideas, questions

[Rob V. <rv...@do...>]

Hi Alexander

 

2  & 4 - Ok I see your points here.  I have adjusted the API so that it
takes IEnumerable<Triple> instead as of revision 626

5 - It would be better to parse the query but Virtuoso's SPARQL syntax is so
complex and extended that it is impractical to do so.  I have an idea for a
way that might give more accurate query type detection in some (but still
not all) cases but I probably won't implement that for the next release
since it'll require some reworking of my SPARQL parser.

 

6 - From a licensing point of view I'm thinking that the Lesser GPL would be
suitable for commercial licensing.  The Lesser GPL allows you to use the
library as-is in a commercial product and doesn't require you to open source
your code or allow users to redistribute your code (obviously they can still
redistributed dotNetRDF as it's still free software).  If you change the
library directly then you are required to publish the changed library under
the LGPL but if you are just building stuff on top of the library then that
code can stay closed source.  In order to grant you such a license there
will be a nominal license fee since it is my intention that the library
remain under the full GPL - I'm discussing with colleagues what this fee
should be.   Or we may decide to move to a different license such as the BSD
license which would make it easier for people to use the API in commercial
products.

 

With regards to RDFa support there is an RDFa parser in the repository which
will be part of the next release which will hopefully be in the next two
weeks or so. There is also an updated HtmlWriter class which embeds the RDFa
representing the Triples it is displaying in an HTML table.

 

Basically I have done everything I wanted to do for the next release but
there have been some serious issues with Virtuoso 6 support which are due to
bugs in Virtuoso 6 and it's ADO.Net provider which I have been trying to
resolve with the help of my contacts at OpenLink.  Until I can confirm that
their fixes work with the latest versions of my code I can't do an official
release.

 

Rob Vesse

 

From: Alexander Sidorov [mailto:ale...@gm...] 
Sent: 22 February 2010 09:18
To: rv...@do...
Cc: dotNetRDF Bug Report tracking and resolution;
dot...@li...
Subject: Re: [dotNetRDF-bugs] Bugs, problems, ideas, questions

 

Hi Rob,

2. It is unreal for me to load graph, modify it and then save, because my
graph may be very and very big. What I just need is to delete or add some
triples, that's why I use Update graph method.

4. I'm not sure if I understood you right... but it looks like you don't
need to implement one more overload: you just need to change List to
IEnumerable. Generally it is a good approach to use the lowest type in
hierarchy you can (GoF book tells a lot about it). And if you are buffering
triples in lists, changin UpdateGraph method signature to IEnumerable won't
change you code logic as List implements IEnumerable.

I agree that overhead is not so much, but nevertheless I don't see any
reason to keep List variables there: UpdateGraph method implementation
doesn't need any functionality except IEnumerable provides.

5. Yes, it would be better to parse the query and check it more accurate.

6. The one reason is that I want to use dotnetRDF in my commercial project.
Also I wanted to implement RDFa publishing tool. But I read in your twitter
that you have the same plans too (haven't you started?). So we could make it
together. But as I said, first of all, I need the ability to use this code
at commercial project.

Regards,
Alexander

2010/2/21 Rob Vesse <rv...@do...>

Hi Alexander

Thanks for reporting the bugs and contributing your ideas.

1 - I have fixed this as suggested as of revision 625

2 - The UpdateGraph is intended primarily for use internally by the API, it
happens to be a public method since it's an interface method.  It's designed
to combine the two operations since from an IO point of view there
operations are typically achieved via the same mechanism.  It's intended use
is for persisting changes to Graphs as they happen, if you are making a
fixed number/predetermined changes to a Graph then it's typically best to
load it using the LoadGraph() method, change it then persist it back to the
store using the SaveGraph() method.

3 - I have altered the implementation of the UpdateGraph method in all
existing IGenericIOManager implementations so they accept null arguments for
either list as of revision 625

4 - UpdateGraph uses lists since as I said wrt point 2 it's designed
primarily for internal usage.  Where it's used internally we're buffering
triples that are to be added/removed in lists and then persisting them in a
bulk operation for efficiency purposes.  I may add an additional overload in
the future which accepts IEnumerable<Triple> but I don't really see the
need.

With the example you gave why not just use the SaveGraph() method instead -
I assume you're adding to an existing Graph and want to preserve what's
already in the Graph in Virtuoso?

Creating a list doesn't really have that much overhead associated with it,
typically the triples are stored in a dictionary/hash table anyway.
Converting an enumerable to a list doesn't actually use that much memory
since you aren't physically copying the triples you're only creating copies
of the references to the triples (total overhead roughly 2/4 bytes per
triple - depends on whether you're running 32/64 bit system)

5 - Fix is applied as of revision 625 - the fix is still slightly
unsatisfactory since what if the query is something like ASK WHERE {?select
?p ?o} that will be flagged as a select query when it is not.

6 - I will get back to you about licensing, I have another similar question
from another user and I need to look into compatibility of different
licenses before I can answer your question.  Is there any particular reason
why you don't like the GPL?

Rob Vesse

  _____  

From: "Alexander Sidorov" <ale...@gm...>

Sent: Saturday, February 20, 2010 8:57 PM

To: dot...@li...

Subject: [dotNetRDF-bugs] Bugs, problems, ideas, questions



Hello!

1. VirtuosoManager.LoadNode method doesn't work correctly with queries that
contain OPTIONAL clause. Such queries return DbNull for result sets at which
optional variables are not set. I have just added one more "else if" and it
works nice:
            else if (n is DBNull)
            {
                temp = null;
            }
2. Why not to split UpdateGraph method to AddToGraph and RemoveFromGraph
methods? I think it would be more convenient for most usecases.

3. Method UpdateGraph (at least in VirtuosoManager) throws exception when
removals variable is null. That's why I have to pass empty list to make my
addition-only UpdateGraph call work. I think it would be nice to make this
query work with additions or/and removals equal to null.

4. Why does method UpdateGraph has List<Triple> but not IEnumerable<Triple>
parameters? It is inconvenient, for example, when I would like to save
graph's triples:

            Graph graph = new Graph();
            RdfXmlParser parser = new RdfXmlParser();
            parser.Load(graph, fileName);

            this._virtuosoManager.

UpdateGraph(graphUri, graph.Triples.ToList(), new List<VDS.RDF.Triple>());

I have to create the list and it makes my code less efficient (imagine big
graph).

5. VirtuosoManager.Query method contains the following code:

                else if (results.Rows.Count == 1 && results.Columns.Count ==
1)
                {
                    //Single Row and Column implies ASK/DESCRIBE/CONSTRUCT
results

I have some SELECT-queries that return one variable and sometimes one
result. And because of the previous code my results are lost (because I
expect my variable, but not variable called Result. I think it would be nice
to make simple check (just search ask, describe or construct words in the
query) to determine is this SELECT-query or not.

6. Is there any way to get dotnetRDF library (only library) without any GPL
dependencies under BSD or similar license?

That's all for today :)

Regards,
Alexander

 

 

Re: [dotNetRDF-develop] [dotNetRDF-bugs] Bugs, problems, ideas, questions

[Alexander S. <ale...@gm...>]

Hi Rob,

2. It is unreal for me to load graph, modify it and then save, because my
graph may be very and very big. What I just need is to delete or add some
triples, that's why I use Update graph method.

4. I'm not sure if I understood you right... but it looks like you don't
need to implement one more overload: you just need to change List to
IEnumerable. Generally it is a good approach to use the lowest type in
hierarchy you can (GoF book tells a lot about it). And if you are buffering
triples in lists, changin UpdateGraph method signature to IEnumerable won't
change you code logic as List implements IEnumerable.

I agree that overhead is not so much, but nevertheless I don't see any
reason to keep List variables there: UpdateGraph method implementation
doesn't need any functionality except IEnumerable provides.

5. Yes, it would be better to parse the query and check it more accurate.

6. The one reason is that I want to use dotnetRDF in my commercial project.
Also I wanted to implement RDFa publishing tool. But I read in your twitter
that you have the same plans too (haven't you started?). So we could make it
together. But as I said, first of all, I need the ability to use this code
at commercial project.

Regards,
Alexander

2010/2/21 Rob Vesse <rv...@do...>

> Hi Alexander
>
> Thanks for reporting the bugs and contributing your ideas.
>
> 1 - I have fixed this as suggested as of revision 625
>
> 2 - The UpdateGraph is intended primarily for use internally by the API, it
> happens to be a public method since it's an interface method.  It's designed
> to combine the two operations since from an IO point of view there
> operations are typically achieved via the same mechanism.  It's intended use
> is for persisting changes to Graphs as they happen, if you are making a
> fixed number/predetermined changes to a Graph then it's typically best to
> load it using the LoadGraph() method, change it then persist it back to the
> store using the SaveGraph() method.
>
> 3 - I have altered the implementation of the UpdateGraph method in all
> existing IGenericIOManager implementations so they accept null arguments for
> either list as of revision 625
>
> 4 - UpdateGraph uses lists since as I said wrt point 2 it's designed
> primarily for internal usage.  Where it's used internally we're buffering
> triples that are to be added/removed in lists and then persisting them in a
> bulk operation for efficiency purposes.  I may add an additional overload in
> the future which accepts IEnumerable<Triple> but I don't really see the
> need.
>
> With the example you gave why not just use the SaveGraph() method instead -
> I assume you're adding to an existing Graph and want to preserve what's
> already in the Graph in Virtuoso?
>
> Creating a list doesn't really have that much overhead associated with it,
> typically the triples are stored in a dictionary/hash table anyway.
> Converting an enumerable to a list doesn't actually use that much memory
> since you aren't physically copying the triples you're only creating copies
> of the references to the triples (total overhead roughly 2/4 bytes per
> triple - depends on whether you're running 32/64 bit system)
>
> 5 - Fix is applied as of revision 625 - the fix is still slightly
> unsatisfactory since what if the query is something like ASK WHERE {?select
> ?p ?o} that will be flagged as a select query when it is not.
>
> 6 - I will get back to you about licensing, I have another similar question
> from another user and I need to look into compatibility of different
> licenses before I can answer your question.  Is there any particular reason
> why you don't like the GPL?
>
> Rob Vesse
>
> ------------------------------
> *From*: "Alexander Sidorov" <ale...@gm...>
> *Sent*: Saturday, February 20, 2010 8:57 PM
> *To*: dot...@li...
> *Subject*: [dotNetRDF-bugs] Bugs, problems, ideas, questions
>
>
> Hello!
>
> 1. VirtuosoManager.LoadNode method doesn't work correctly with queries that
> contain OPTIONAL clause. Such queries return DbNull for result sets at which
> optional variables are not set. I have just added one more "else if" and it
> works nice:
>             else if (n is DBNull)
>             {
>                 temp = null;
>             }
> 2. Why not to split UpdateGraph method to AddToGraph and RemoveFromGraph
> methods? I think it would be more convenient for most usecases.
>
> 3. Method UpdateGraph (at least in VirtuosoManager) throws exception when
> removals variable is null. That's why I have to pass empty list to make my
> addition-only UpdateGraph call work. I think it would be nice to make this
> query work with additions or/and removals equal to null.
>
> 4. Why does method UpdateGraph has List<Triple> but not IEnumerable<Triple>
> parameters? It is inconvenient, for example, when I would like to save
> graph's triples:
>
>             Graph graph = new Graph();
>             RdfXmlParser parser = new RdfXmlParser();
>             parser.Load(graph, fileName);
>
>             this._virtuosoManager.
> UpdateGraph(graphUri, *graph.Triples.ToList()*, new
> List<VDS.RDF.Triple>());
>
> I have to create the list and it makes my code less efficient (imagine big
> graph).
>
> 5. VirtuosoManager.Query method contains the following code:
>
>                 else if (results.Rows.Count == 1 && results.Columns.Count
> == 1)
>                 {
>                     //Single Row and Column implies ASK/DESCRIBE/CONSTRUCT
> results
>
> I have some SELECT-queries that return one variable and sometimes one
> result. And because of the previous code my results are lost (because I
> expect my variable, but not variable called Result. I think it would be nice
> to make simple check (just search ask, describe or construct words in the
> query) to determine is this SELECT-query or not.
>
> 6. Is there any way to get dotnetRDF library (*only library*) without any
> GPL dependencies under BSD or similar license?
>
> That's all for today :)
>
> Regards,
> Alexander
>
>

Re: [dotNetRDF-develop] dotNetRDF commercial license

[Rob V. <rv...@do...>]

Hi Igor

Thanks for your interest.  I'm not exactly sure on pricing or under what 
license the library should be published for commercial use, I will get back 
to you by the end of the week (Friday 26th) about this.

I assume that using the library under the GNU GPL would not be feasible for 
your commercial needs?

Rob Vesse

----------------------------------------
From: "Igor Shakola" <igo...@gm...>
Sent: Friday, February 19, 2010 3:49 PM
To: rv...@do...
Subject: dotNetRDF commercial license 

Hi Rob,
           I have explored your library and I must say that I really like 
it ( both architecture and code style ).                      Our company 
would like to use it in a commercial project.
           Is there any way to get\buy a commercial license? How much does 
it cost? Best,Igor
 

Re: [dotNetRDF-develop] [dotNetRDF-bugs] Bugs, problems, ideas, questions

[Rob V. <rv...@do...>]

Hi Alexander

Thanks for reporting the bugs and contributing your ideas.

1 - I have fixed this as suggested as of revision 625

2 - The UpdateGraph is intended primarily for use internally by the API, it 
happens to be a public method since it's an interface method.  It's 
designed to combine the two operations since from an IO point of view there 
operations are typically achieved via the same mechanism.  It's intended 
use is for persisting changes to Graphs as they happen, if you are making a 
fixed number/predetermined changes to a Graph then it's typically best to 
load it using the LoadGraph() method, change it then persist it back to the 
store using the SaveGraph() method.

3 - I have altered the implementation of the UpdateGraph method in all 
existing IGenericIOManager implementations so they accept null arguments 
for either list as of revision 625

4 - UpdateGraph uses lists since as I said wrt point 2 it's designed 
primarily for internal usage.  Where it's used internally we're buffering 
triples that are to be added/removed in lists and then persisting them in a 
bulk operation for efficiency purposes.  I may add an additional overload 
in the future which accepts IEnumerable<Triple> but I don't really see the 
need.

With the example you gave why not just use the SaveGraph() method instead - 
I assume you're adding to an existing Graph and want to preserve what's 
already in the Graph in Virtuoso?

Creating a list doesn't really have that much overhead associated with it, 
typically the triples are stored in a dictionary/hash table anyway.  
Converting an enumerable to a list doesn't actually use that much memory 
since you aren't physically copying the triples you're only creating copies 
of the references to the triples (total overhead roughly 2/4 bytes per 
triple - depends on whether you're running 32/64 bit system)

5 - Fix is applied as of revision 625 - the fix is still slightly 
unsatisfactory since what if the query is something like ASK WHERE {?select 
?p ?o} that will be flagged as a select query when it is not.

6 - I will get back to you about licensing, I have another similar question 
from another user and I need to look into compatibility of different 
licenses before I can answer your question.  Is there any particular reason 
why you don't like the GPL?

Rob Vesse

----------------------------------------
From: "Alexander Sidorov" <ale...@gm...>
Sent: Saturday, February 20, 2010 8:57 PM
To: dot...@li...
Subject: [dotNetRDF-bugs] Bugs, problems, ideas, questions 

Hello!

1. VirtuosoManager.LoadNode method doesn't work correctly 
with queries that contain OPTIONAL clause. Such queries return DbNull 
for result sets at which optional variables are not set. I have just 
added one more "else if" and it works nice:

            else if (n is DBNull)
            {
                
temp = null;
            }
2. Why not to split UpdateGraph method 
to AddToGraph and RemoveFromGraph methods? I think it would be more 
convenient for most usecases.

3. Method UpdateGraph (at least in VirtuosoManager) throws exception
 when removals variable is null. That's why I have to pass empty list to
 make my addition-only UpdateGraph call work. I think it would be nice 
to make this query work with additions or/and removals equal to null.

4. Why does method UpdateGraph has List<Triple> but not 
IEnumerable<Triple> parameters? It is inconvenient, for example, 
when I would like to save graph's triples:

            Graph 
graph = new Graph();

            RdfXmlParser parser = new RdfXmlParser();
            
parser.Load(graph, fileName);

            this._virtuosoManager.UpdateGraph(graphUri,
 graph.Triples.ToList(), new List<VDS.RDF.Triple>());

I have to create the list and it makes my code less efficient 
(imagine big graph).

5. VirtuosoManager.Query method contains the
 following code:

                else if (results.Rows.Count == 1
 && results.Columns.Count == 1)

                {
                    //Single Row and Column implies
 ASK/DESCRIBE/CONSTRUCT results

I have some SELECT-queries that 
return one variable and sometimes one result. And because of the 
previous code my results are lost (because I expect my variable, but not
 variable called Result. I think it would be nice to make simple check 
(just search ask, describe or construct words in the query) to determine
 is this SELECT-query or not.

6. Is there any way to get dotnetRDF library (only library) 
without any GPL dependencies under BSD or similar license?

That's
 all for today :)

Regards,
Alexander

 

[dotNetRDF-develop] Version 0.1.1 Alpha

[Rob V. <ra...@ec...>]

Version 0.1.1 Alpha of the Library was released this past week and includes
among other things the following improvements:

 

.         General Improvements

o   Many minor bug fixes and optimisations

o   Improved in-memory storage for Nodes and Triples which facilitates the
Parser improvements

.         Parsing Improvements

o   All parsers are now around 20x faster

o   Added parsers for RDF/JSON and TriG

o   Support for parsing directly from Strings with format auto-detection

.         Serialization Improvements

o   All NTriple type writers are around 200x faster

o   Added an additional RDF/XML writers which is around 80x faster (old
serializers for this are still quite slow)

o   Added writers for RDF/JSON and TriG

o   Support for writing to any TextWriter rather than just to a StreamWriter

.         Storage Improvements

o   Support for Talis Platform

o   Support for Virtuoso Universal Server

o   Revised Store format offers improved read speeds and improved write
speeds in some situations

.         ASP.Net Integration

o   Added some SPARQL Handlers allowing for the easy integration of SPARQL
Endpoints into websites

o   Added some Resource lookup Handlers allowing for easy integration of
linked data publishing into websites

 

You can download the latest versions from http://www.dotnetrdf.org and there
is now a User Guide located at
http://www.dotnetrdf.org/content.asp?pageID=User%20Guide

 

Rob Vesse

 

dotNetRDF Lead Developer

================================================================

Developer Discussion & Feature Request -
dot...@li...

Bug Reports - dot...@li...

User Help & Support - dot...@li...

 

Website: http://www.dotnetrdf.org

API: http://www.dotnetrdf.org/content.asp?pageID=API

Intellisense API: http://www.dotnetrdf.org/api/

================================================================

 

[dotNetRDF-develop] Test Message

[Rob V. <ra...@ec...>]

Testing to ensure that the dotNetRDF Mailing Lists are up and running
successfully!

 

Rob Vesse

dotNetRDF Lead Developer

================================================================

Developer Discussion & Feature Request -
dot...@li...

Bug Reports - dot...@li...

User Help & Support - dot...@li...

 

Website: http://www.dotnetrdf.org

API: http://www.dotnetrdf.org/content.asp?pageID=API

Intellisense API: http://www.dotnetrdf.org/api/

================================================================