{"id":172,"date":"2012-03-08T11:55:53","date_gmt":"2012-03-08T16:55:53","guid":{"rendered":"http:\/\/www.thefaberfamily.org\/search-smith\/?p=172"},"modified":"2012-03-08T12:05:57","modified_gmt":"2012-03-08T17:05:57","slug":"coldfusion-and-solr-dealing-with-the-results","status":"publish","type":"post","link":"http:\/\/www.thefaberfamily.org\/search-smith\/2012\/03\/coldfusion-and-solr-dealing-with-the-results\/","title":{"rendered":"ColdFusion and Solr: Dealing with the results"},"content":{"rendered":"

The Solr web service allows you to return results in either XML format or JSON (the format is XML by default; to return results in JSON format, add the parameter “wt=json” to your Solr query string). Suppose we run a query on the Solr collection myindex<\/strong>. There are three ways we can search this collection: (1) we could use the <cfsearch><\/code> tag; (2) we could use the Solr web service and return XML; or (3) we could use the Solr web service and return JSON. We’ve talked about <cfsearch><\/code> and its limitations before<\/a> so I’ll limit this discussion to the second and third options.<\/p>\n

XML:<\/strong><\/p>\n

<cfhttp url=\"http:\/\/localhost:8983\/solr\/myindex?q=*:*&fl=*,score\" result=\"myresult\" \/><\/pre>\n
JSON:<\/strong><\/p>\n
<cfhttp url=\"http:\/\/localhost:8983\/solr\/myindex?q=*:*&fl=*,score&wt=json\" result=\"myresult\" \/><\/pre>\n
In each case (XML or JSON), ColdFusion has powerful functions that help you manage the data without needing to parse it manually. Typically I create a friendly query that I can return to the front-end developer that he can use in place of a SQL query or <cfsearch><\/code> result.<\/p>\n
<cfset search_results = queryNew(\"id,title,description,pubdate,journal_name,author_name,num_reads,score\"\r\n                              \u00a0, \"CF_SQL_INTEGER,CF_SQL_VARCHAR,CF_SQL_CLOB,CF_SQL_DATE,CF_SQL_VARCHAR,CF_SQL_VARCHAR,CF_SQL_INTEGER,CF_SQL_DOUBLE\")\r\n\/>\r\n<!--- We're using our articles index mentioned in a previous post<\/a> ---><\/pre>\n
XML:<\/strong><\/p>\n
<cfif isXML(myresult)>\r\n    <cfset xml_result = XMLParse(myresult.fileContent) \/>\r\n    <!--- continue processing --->\r\n<\/cfif><\/pre>\n
JSON:<\/strong><\/p>\n
<cfif isJSON(myresult)>\r\n    <cfset json_result = deserializeJSON(myresult.fileContent) \/>\r\n    <!--- continue processing --->\r\n<\/cfif><\/pre>\n
In either case we will iterate over our results structure and put the results in our friendly query.<\/p>\n
JSON:<\/strong>
\nThe JSON structure is particularly friendly for our purposes. First, let’s get the number of results and the maximum score:<\/p>\n
<cfset result_cnt = json_result.response.numFound \/>\r\n<cfset max_score = json_result.response.maxScore \/><\/pre>\n
These fields aren’t absolutely necessary, of course. In particular, maxScore seems superfluous but it might be useful if you’re converting from Verity to Solr and need scores in a % format. The Verity search engine scores results between 0 and 1, which is easily converted to a percentage; while Solr has no maximum score. So to get a Verity-style score, simply divide each result’s score by maxScore.<\/p>\n
Now we simply loop over the docs <\/code>array of the response:<\/p>\n
<cfloop array=\"#json_result.response.docs#\" index=\"doc\">\r\n    <cfif structKeyExists(doc, \"id\") AND structKeyExists(doc, \"title\")>\r\n        <!--- Both id and title are absolutely required --->\r\n        <cfset queryAddRow(search_results) \/>\r\n        <cfset querySetCell(search_results, \"id\", doc[id]) \/>\r\n        <cfset querySetCell(search_results, \"title\", doc[title]) \/>\r\n        <cfset querySetCell(search_results, \"score\", doc[score] \/ max_score) \/>\r\n       \u00a0<cfif structKeyExists(doc, \"description\")>\r\n            <cfset querySetCell(search_results, \"description\", doc[description]) \/>\r\n        <\/cfif>\r\n        <cfif structKeyExists(doc, \"pub_date\")>\r\n            <cfset querySetCell(search_results, \"pub_date\", doc[pub_date]) \/>\r\n        <\/cfif>\r\n        <cfif structKeyExists(doc, \"journal_name\")>\r\n            <cfset querySetCell(search_results, \"journal_name\", doc[journal_name]) \/>\r\n        <\/cfif>\r\n        <cfif structKeyExists(doc, \"author_name\")>\r\n            <cfset querySetCell(search_results, \"author_name\", doc[author_name]) \/>\r\n        <\/cfif>\r\n        <cfif structKeyExists(doc, \"read_cnt\")>\r\n            <cfset querySetCell(search_results, \"read_cnt\", doc[read_cnt]) \/>\r\n        <\/cfif>\r\n    <\/cfif>\r\n<\/cfloop><\/pre>\n
Dealing with XML results is a bit more complicated so I will discuss that in a subsequent post or in an update to this one. Suffice it to say that the approach will be very similar – we will iterate over the results and store them in a friendly query.<\/p>\n
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