上传至MarkLogic时如何强制指定XML contentType？

我通过自制HTTP服务器上传带有明确.xml扩展名的文件，但MarkLogic却在本地数据库中将其保存为.txt文件，导致无法执行XML相关查询。

我的上传XQuery函数如下：

declare function local:uploadFile() { 
  let $filename := xdmp:get-request-field-filename("upload") 
  let $file := xdmp:get-request-field("upload") 
  let $collection := "semansysdocs" 
  return xdmp:document-insert( 
    $filename, 
    $file, 
    xdmp:default-permissions(), 
    (xdmp:default-collections(), $collection) 
  ) 
};

示例上传文档（文件名：Prod223_1982_03975172_20170430.xml）：

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="http://www.companieshouse.gov.uk/ef/xbrl/uk/fr/gaap/ae/2009-06-21/stylesheet/CH-AE-dormant-stylesheet.xsl"?>
<xbrl xmlns="http://www.xbrl.org/2003/instance" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ae="http://www.companieshouse.gov.uk/ef/xbrl/uk/fr/gaap/ae/2009-06-21" xmlns:gc="http://www.xbrl.org/uk/fr/gcd/2004-12-01" xmlns:html="http://www.w3.org/1999/xhtml" xmlns:iso4217="http://www.xbrl.org/2003/iso4217" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:pt="http://www.xbrl.org/uk/fr/gaap/pt/2004-12-01" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink">
<link:schemaRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="http://www.companieshouse.gov.uk/ef/xbrl/uk/fr/gaap/ae/2009-06-21/uk-gaap-ae-2009-06-21.xsd" xlink:type="simple"/>
<ae:CompanyDormant contextRef="y2017">true</ae:CompanyDormant>
<gc:EntityNames>
<gc:EntityCurrentLegalName contextRef="y2017">HUNTS GROUP PLC</gc:EntityCurrentLegalName>
</gc:EntityNames>
<ae:CompanyIdentifyingNumbers>
<ae:CompaniesHouseRegisteredNumber contextRef="y2017">03975172</ae:CompaniesHouseRegisteredNumber>
</ae:CompanyIdentifyingNumbers>
<gc:StatementDatesPeriodsCovered>
<gc:BalanceSheetDate contextRef="e2017">2017-04-30</gc:BalanceSheetDate>
</gc:StatementDatesPeriodsCovered>
<pt:ShareholderFunds precision="6" contextRef="e2017" unitRef="GBP">12500</pt:ShareholderFunds>
<pt:ShareholderFunds precision="6" contextRef="e2016" unitRef="GBP">12500</pt:ShareholderFunds>
<pt:NetAssetsLiabilitiesIncludingPensionAssetLiability precision="5" contextRef="e2017" unitRef="GBP">12500</pt:NetAssetsLiabilitiesIncludingPensionAssetLiability>
<pt:NetAssetsLiabilitiesIncludingPensionAssetLiability precision="5" contextRef="e2016" unitRef="GBP">12500</pt:NetAssetsLiabilitiesIncludingPensionAssetLiability>
<pt:CashBankInHand precision="5" contextRef="e2017" unitRef="GBP">12500</pt:CashBankInHand>
<pt:CashBankInHand precision="5" contextRef="e2016" unitRef="GBP">12500</pt:CashBankInHand>
<pt:EquityAuthorisedDetails>
<pt:TypeOrdinaryShare contextRef="y2017">Ordinary</pt:TypeOrdinaryShare>
<pt:NumberOrdinarySharesAuthorised precision="INF" contextRef="e2017" unitRef="shares">50000</pt:NumberOrdinarySharesAuthorised>
<pt:ParValueOrdinaryShare precision="INF" contextRef="y2017" unitRef="GBP">1</pt:ParValueOrdinaryShare>
</pt:EquityAuthorisedDetails>
<pt:DetailsOrdinarySharesAllotted>
<pt:TypeOrdinaryShare contextRef="y2017">Ordinary</pt:TypeOrdinaryShare>
<pt:ParValueOrdinaryShare precision="INF" contextRef="y2017" unitRef="GBP">1</pt:ParValueOrdinaryShare>
<pt:ValueOrdinarySharesAllotted precision="5" contextRef="e2017" unitRef="GBP">12500</pt:ValueOrdinarySharesAllotted>
<pt:ValueOrdinarySharesAllotted precision="5" contextRef="e2016" unitRef="GBP">12500</pt:ValueOrdinarySharesAllotted>
<pt:NumberOrdinarySharesAllotted precision="INF" contextRef="e2017" unitRef="shares">12500</pt:NumberOrdinarySharesAllotted>
</pt:DetailsOrdinarySharesAllotted>
<pt:DateApproval contextRef="e2017">2017-10-13</pt:DateApproval>
<pt:ApprovalDetails>
<pt:NameApprovingDirector contextRef="y2017">Mr. David Charles Hunt</pt:NameApprovingDirector>
</pt:ApprovalDetails>
<ae:CompanyEntitledToExemptionUnderSection480CompaniesAct2006 contextRef="y2017">true</ae:CompanyEntitledToExemptionUnderSection480CompaniesAct2006>
<ae:MembersHaveNotRequiredCompanyToObtainAnAudit contextRef="y2017">true</ae:MembersHaveNotRequiredCompanyToObtainAnAudit>
<ae:DirectorsAcknowledgeTheirResponsibilitiesUnderCompaniesAct contextRef="y2017">true</ae:DirectorsAcknowledgeTheirResponsibilitiesUnderCompaniesAct>
<ae:AccountsAreInAccordanceWithSpecialProvisionsCompaniesActRelatingToSmallCompanies contextRef="y2017">true</ae:AccountsAreInAccordanceWithSpecialProvisionsCompaniesActRelatingToSmallCompanies>
<unit id="shares">
<measure>xbrli:shares</measure>
</unit>
<unit id="GBP">
<measure>iso4217:GBP</measure>
</unit>
<unit id="pure">
<measure>xbrli:pure</measure>
</unit>
<context id="y2017">
<entity>
<identifier scheme="/results">HUNTS GROUP PLC</identifier>
</entity>
<period>
<startDate>2016-05-01</startDate>
<endDate>2017-04-30</endDate>
</period>
</context>
<context id="y2016">
<entity>
<identifier scheme="/results">HUNTS GROUP PLC</identifier>
</entity>
<period>
<startDate>2015-05-01</startDate>
<endDate>2016-04-30</endDate>
</period>
</context>
<context id="s2016">
<entity>
<identifier scheme="/results">HUNTS GROUP PLC</identifier>
</entity>
<period>
<instant>2015-04-30</instant>
</period>
</context>
<context id="e2016">
<entity>
<identifier scheme="/results">HUNTS GROUP PLC</identifier>
</entity>
<period>
<instant>2016-04-30</instant>
</period>
</context>
<context id="s2017">
<entity>
<identifier scheme="/results">HUNTS GROUP PLC</identifier>
</entity>
<period>
<instant>2016-04-30</instant>
</period>
</context>
<context id="e2017">
<entity>
<identifier scheme="/results">HUNTS GROUP PLC</identifier>
</entity>
<period>
<instant>2017-04-30</instant>
</period>
</context>
<ae:CompaniesHouseDocumentAuthentication contextRef="y2017"></ae:CompaniesHouseDocumentAuthentication>
<ae:DateAccountsReceived contextRef="e2017">2017-10-16</ae:DateAccountsReceived>
</xbrl>

这是一份XBRL文档（属于XML的扩展格式），但我没法在xdmp:document-insert()里直接指定contentType，请问有什么办法能强制设置它的XML contentType？

解决方案 #

这个问题的核心是你现在插入的是字符串类型的内容，MarkLogic会默认把字符串识别为text/plain类型，哪怕文件名带.xml扩展名也没用。下面有几个靠谱的解决办法：

1. 将上传内容解析为XML节点后插入 #

直接把$file从字符串转换成XML节点，这样MarkLogic会自动识别为XML类型，不需要额外指定contentType。修改你的函数：

declare function local:uploadFile() { 
  let $filename := xdmp:get-request-field-filename("upload") 
  let $file := xdmp:get-request-field("upload") 
  let $xml-content := fn:parse-xml($file)  <!-- 关键：把字符串解析成XML节点 -->
  let $collection := "semansysdocs" 
  return xdmp:document-insert( 
    $filename, 
    $xml-content,  <!-- 插入节点而非字符串 -->
    xdmp:default-permissions(), 
    (xdmp:default-collections(), $collection) 
  ) 
};

注意：如果上传的XML格式不合法，fn:parse-xml()会抛出错误，你可以考虑用try/catch来处理异常情况。

2. 使用xdmp:document-insert的选项参数设置contentType #

MarkLogic的xdmp:document-insert支持第五个参数作为选项，你可以通过xdmp:document-insert-options()来指定contentType。修改后的函数：

declare function local:uploadFile() { 
  let $filename := xdmp:get-request-field-filename("upload") 
  let $file := xdmp:get-request-field("upload") 
  let $collection := "semansysdocs" 
  let $options := xdmp:document-insert-options(
    <options xmlns="xdmp:document-insert">
      <content-type>application/xml</content-type>
    </options>
  )
  return xdmp:document-insert( 
    $filename, 
    $file, 
    xdmp:default-permissions(), 
    (xdmp:default-collections(), $collection),
    $options  <!-- 添加选项参数 -->
  ) 
};

这个方法适合你不想解析XML（比如担心解析错误），但又要强制设置contentType的场景。

3. 插入后更新文档的metadata #

如果已经有大量错误类型的文档，或者你需要批量修正，可以用xdmp:document-set-properties来更新已插入文档的contentType属性：

xdmp:document-set-properties(
  "/path/to/your/document.xml",
  <properties xmlns="http://marklogic.com/xdmp/document">
    <content-type>application/xml</content-type>
  </properties>
)

不过更推荐在插入时就处理好，避免后续的批量操作。

内容的提问来源于stack exchange，提问作者Mick Remmerswaal