javascript - 如何为 JS 格式化我的 SPARQL？

Question

我正在尝试使用这个 http://landregistry.data.gov.uk/app/qonsole我特别尝试使用“邮政编码中的交易”选项。这是我的 JS。

var query =[
"prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>",
"prefix skos: <http://www.w3.org/2004/02/skos/core#>",
"prefix lrcommon: <http://landregistry.data.gov.uk/def/common/>",
"prefix lrppi: <http://landregistry.data.gov.uk/def/ppi/>",
"prefix xsd: <http://www.w3.org/2001/XMLSchema#>",
"SELECT ?paon ?saon ?street ?town ?county ?postcode ?amount ?date ?category",
"WHERE {",
  "VALUES ?postcode {'PL6 8RU'^^xsd:string}",

  "?addr lrcommon:postcode ?postcode.",

  "?transx lrppi:propertyAddress ?addr ;",
          "lrppi:pricePaid ?amount ;",
          "lrppi:transactionDate ?date ;",
          "lrppi:transactionCategory/skos:prefLabel ?category.",

  "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"].join(" ");

var endpoint = 'http://landregistry.data.gov.uk/app/root/qonsole/query';

var queryUrl = encodeURI( endpoint+"?query="+query);

var fet = fetch(queryUrl)
.then((resp) => resp.json()) // Transform the data into json
  .then(function(data) {
    console.log(data)
    });

但我不断得到:

"Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0"

.then((resp) => resp.json()) // Transform the data into json

.then(function(data) { //This line is the culprit according to console

    console.log(data)
    });

环顾四周，这似乎与尝试使用 .json() 方法有关。

我相信“<”来自查询中的前缀 URL。我该如何解决？

Answer 1

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var endpoint = 'http://landregistry.data.gov.uk/landregistry/query';
var queryUrl = endpoint + '?query=' + encodeURIComponent(query);

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