casbah/server/strmod.js

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/**********************************
MIT License

Copyright (c) 2018 Andrew Siddeley

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exports.substitute=function(sql, params){
	/**************
	Returns a string with substitutions applied to matched substrings within the string.
	1st arrument is the subject string
	2nd argument is an object of key:values
	Where any key matches any portion of 1st argument, that portion is substituted with the corresponding value. 
	
	Why is this function required when db.run has it built in db.run(sql, params, callback) ?
	Because if params have more elements than the sql has placeholders it throws an error
	This function is more forgiving
	*************/
	
	//console.log("sql_params...")
	//ensure these aren't touching terms
	sql=sql.replace(/\(/g, " ( ") 
	sql=sql.replace(/\)/g, " ) ") 
	sql=sql.replace(/=/g, " = ") 
	sql=sql.replace(/,/g , " , ") 
	//console.log("sql after grooming...", sql)
	var terms=sql.split(" ") 
	for (var i in terms){
		
		//term starts with '$' so a parameter, substitute it with it's corresponding vlaue
		if ( terms[i].indexOf("$")==0 ) {
			//console.log("term before...", terms[i].substring(1))
			terms[i]='"'+params[terms[i].substring(1)]+'"'
			//console.log("term after...", terms[i])
		}		
	}
	return terms.join(" ") //unsplit
}