Question

我正在尝试从land注册API（http://landregistry.data.gov.uk/app/hpi/qonsole）获取一些数据并使用SPARQL查询。我是sparql查询的新手，不知道在我的param.query对象中传递什么以及如何传递所需的前缀。

 //myCode
 var req = {
        method: 'GET',
        url: 'http://landregistry.data.gov.uk/landregistry/query',
        headers: { 'Content-type' : 'application/x-www-form-urlencoded',
            'Accept' : 'application/sparql-results+json' },
        params: {
            query :"select ?paon ?saon ?street ?town ?county ?postcode ?amount ?date where {?addr lrcommon:postcode "PL6 8RU"} limit 10",
            format: "json"
        }
    };
    console.log(req)

// SparQL Query
prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
prefix owl: <http://www.w3.org/2002/07/owl#>
prefix xsd: <http://www.w3.org/2001/XMLSchema#>
prefix sr: <http://data.ordnancesurvey.co.uk/ontology/spatialrelations/>
prefix lrhpi: <http://landregistry.data.gov.uk/def/hpi/>
prefix lrppi: <http://landregistry.data.gov.uk/def/ppi/>
prefix skos: <http://www.w3.org/2004/02/skos/core#>
prefix lrcommon: <http://landregistry.data.gov.uk/def/common/>

#-- Returns the Price Paid data from the default graph for each transaction record having
#-- an address with the given postcode.
#-- The postcode to query is set in the line - ?address_instance common:postcode "PL6 8RU"^^xsd:string .


SELECT ?paon ?saon ?street ?town ?county ?postcode ?amount ?date
WHERE
{
?transx lrppi:pricePaid ?amount ;
      lrppi:transactionDate ?date ;
      lrppi:propertyAddress ?addr.

?addr lrcommon:postcode "PL6 8RU"^^xsd:string.
?addr lrcommon:postcode ?postcode.

OPTIONAL {?addr lrcommon:county ?county}
OPTIONAL {?addr lrcommon:paon ?paon}
OPTIONAL {?addr lrcommon:saon ?saon}
OPTIONAL {?addr lrcommon:street ?street}
OPTIONAL {?addr lrcommon:town ?town}
}
ORDER BY ?amount

Answer 1

你到了一半。您可以将Angular的$http服务与您开发的请求对象一起使用（假设您正确填充了查询字符串）。 $http服务返回一个承诺，您可以使用可用的快捷方法（.success和.error）来解析该承诺。对于这些，您可以指定一个回调函数，该函数在响应准备就绪时异步调用。例如：

$http({
    url: 'http://landregistry.data.gov.uk/landregistry/query', 
    headers: { 'Content-type' : 'application/x-www-form-urlencoded',
            'Accept' : 'application/sparql-results+json' },
    method: "GET",
    params: {
            query : "select * where {?s a ?o} limit 10",
            format: "json"
        }
  })

  .success(function(data, status, headers, config) {
    // callback called asynchronously when the response is available 
    $scope.results = data.results.bindings;
   })

  .error(function(data, status, headers, config) { 
    // called asynchronously if an error occurs 
    // or server returns response with an error status
  });

这是一个有效的plunker，它执行上述查询并显示结果。

Answer 2

我认为，您可以使用此答案：How do I POST urlencoded form data with $http in AngularJS?来形成您的请求，并在数据中提供查询：

data: {query: "Put your SPARQL Query here"}

SPARQL查询就是＆＃34; // SparQL Query＆＃34;在您的商家信息中，只是JavaScript字符串中的多行文字。（Creating multiline strings in JavaScript用于JavaScript中的多行字符串）。例如，如果我将它放入文本文件yourquery.txt中，我可以使用curl获取结果：

curl --data-urlencode "query@yourquery.txt" http://landregistry.data.gov.uk/landregistry/query

它返回了很好的json：

{
  "head": {
    "vars": [ "paon" , "saon" , "street" , "town" , "county" , "postcode" , "amount" , "date" ]
  } ,
  "results": {
    "bindings": [
      {
        "paon": { "datatype": "http://www.w3.org/2001/XMLSchema#string" , "type": "typed-literal" , "value": "58" } ,
        "street": { "datatype": "http://www.w3.org/2001/XMLSchema#string" , "type": "typed-literal" , "value": "PATTINSON DRIVE" } ,
        "town": { "datatype": "http://www.w3.org/2001/XMLSchema#string" , "type": "typed-literal" , "value": "PLYMOUTH" } ,
        "county": { "datatype": "http://www.w3.org/2001/XMLSchema#string" , "type": "typed-literal" , "value": "CITY OF PLYMOUTH" } ,
        "postcode": { "datatype": "http://www.w3.org/2001/XMLSchema#string" , "type": "typed-literal" , "value": "PL6 8RU" } ,
        "amount": { "datatype": "http://www.w3.org/2001/XMLSchema#integer" , "type": "typed-literal" , "value": "56000" } ,
        "date": { "datatype": "http://www.w3.org/2001/XMLSchema#date" , "type": "typed-literal" , "value": "1999-11-08" }
      } ,
...
}

NB。我正在使用POST，而不是GET - 这不是必需的。

注：

?addr lrcommon:postcode "PL6 8RU"^^xsd:string.
?addr lrcommon:postcode ?postcode.

这不太好。最好使用VALUES或BIND：

BIND ("PL6 8RU"^^xsd:string AS ?postcode)
?addr lrcommon:postcode ?postcode.

因为这是大概想要的。有关详细信息，请参阅SPARQL Query language specs。

如果需要在查询中使用JavaScript变量，则应该转义该值并使用连接：

'BIND ("' + escapedPostcodeVar + '"^^xsd:string AS ?postcode)'

有关逃生的内容和方法的详细信息，请参阅documentation。

供参考，使用SPARQL查询：

var myquery = 'prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> \n\
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> \n\
prefix owl: <http://www.w3.org/2002/07/owl#> \n\
prefix xsd: <http://www.w3.org/2001/XMLSchema#> \n\
prefix sr: <http://data.ordnancesurvey.co.uk/ontology/spatialrelations/> \n\
prefix lrhpi: <http://landregistry.data.gov.uk/def/hpi/> \n\
prefix lrppi: <http://landregistry.data.gov.uk/def/ppi/> \n\
prefix skos: <http://www.w3.org/2004/02/skos/core#> \n\
prefix lrcommon: <http://landregistry.data.gov.uk/def/common/> \n\
 \n\
SELECT ?paon ?saon ?street ?town ?county ?postcode ?amount ?date \n\
WHERE \n\
{ \n\
BIND ("PL6 8RU"^^xsd:string AS ?postcode) \n\
 \n\
?addr lrcommon:postcode ?postcode. \n\
 \n\
?transx lrppi:pricePaid ?amount ; \n\
      lrppi:transactionDate ?date ; \n\
      lrppi:propertyAddress ?addr. \n\
 \n\
OPTIONAL {?addr lrcommon:county ?county} \n\
OPTIONAL {?addr lrcommon:paon ?paon} \n\
OPTIONAL {?addr lrcommon:saon ?saon} \n\
OPTIONAL {?addr lrcommon:street ?street} \n\
OPTIONAL {?addr lrcommon:town ?town} \n\
} \n\
ORDER BY ?amount \n\
LIMIT 10'

然后在$ http：

params: {query: myquery}

如何读取SPARQL查询并通过$ http.get传递

2 个答案: