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package handlers
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import (
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"encoding/json"
"log"
"net/http"
"strings"
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"time"
)
type Price struct {
PriceId int64
SecurityId int64
CurrencyId int64
Date time . Time
Value string // String representation of decimal price of Security in Currency units, suitable for passing to big.Rat.SetString()
RemoteId string // unique ID from source, for detecting duplicates
}
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type PriceList struct {
Prices * [ ] * Price ` json:"prices" `
}
func ( p * Price ) Read ( json_str string ) error {
dec := json . NewDecoder ( strings . NewReader ( json_str ) )
return dec . Decode ( p )
}
func ( p * Price ) Write ( w http . ResponseWriter ) error {
enc := json . NewEncoder ( w )
return enc . Encode ( p )
}
func ( pl * PriceList ) Read ( json_str string ) error {
dec := json . NewDecoder ( strings . NewReader ( json_str ) )
return dec . Decode ( pl )
}
func ( pl * PriceList ) Write ( w http . ResponseWriter ) error {
enc := json . NewEncoder ( w )
return enc . Encode ( pl )
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}
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func CreatePriceIfNotExist ( tx * Tx , price * Price ) error {
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if len ( price . RemoteId ) == 0 {
// Always create a new price if we can't match on the RemoteId
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err := tx . Insert ( price )
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if err != nil {
return err
}
return nil
}
var prices [ ] * Price
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_ , err := tx . Select ( & prices , "SELECT * from prices where SecurityId=? AND CurrencyId=? AND Date=? AND Value=?" , price . SecurityId , price . CurrencyId , price . Date , price . Value )
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if err != nil {
return err
}
if len ( prices ) > 0 {
return nil // price already exists
}
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err = tx . Insert ( price )
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if err != nil {
return err
}
return nil
}
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func GetPrice ( tx * Tx , priceid , userid int64 ) ( * Price , error ) {
var p Price
err := tx . SelectOne ( & p , "SELECT * from prices where PriceId=? AND SecurityId IN (SELECT SecurityId FROM securities WHERE UserId=?)" , priceid , userid )
if err != nil {
return nil , err
}
return & p , nil
}
func GetPrices ( tx * Tx , userid int64 ) ( * [ ] * Price , error ) {
var prices [ ] * Price
_ , err := tx . Select ( & prices , "SELECT * from prices where SecurityId IN (SELECT SecurityId FROM securities WHERE UserId=?)" , userid )
if err != nil {
return nil , err
}
return & prices , nil
}
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// Return the latest price for security in currency units before date
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func GetLatestPrice ( tx * Tx , security , currency * Security , date * time . Time ) ( * Price , error ) {
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var p Price
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err := tx . SelectOne ( & p , "SELECT * from prices where SecurityId=? AND CurrencyId=? AND Date <= ? ORDER BY Date DESC LIMIT 1" , security . SecurityId , currency . SecurityId , date )
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if err != nil {
return nil , err
}
return & p , nil
}
// Return the earliest price for security in currency units after date
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func GetEarliestPrice ( tx * Tx , security , currency * Security , date * time . Time ) ( * Price , error ) {
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var p Price
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err := tx . SelectOne ( & p , "SELECT * from prices where SecurityId=? AND CurrencyId=? AND Date >= ? ORDER BY Date ASC LIMIT 1" , security . SecurityId , currency . SecurityId , date )
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if err != nil {
return nil , err
}
return & p , nil
}
// Return the price for security in currency closest to date
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func GetClosestPrice ( tx * Tx , security , currency * Security , date * time . Time ) ( * Price , error ) {
earliest , _ := GetEarliestPrice ( tx , security , currency , date )
latest , err := GetLatestPrice ( tx , security , currency , date )
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// Return early if either earliest or latest are invalid
if earliest == nil {
return latest , err
} else if err != nil {
return earliest , nil
}
howlate := earliest . Date . Sub ( * date )
howearly := date . Sub ( latest . Date )
if howearly < howlate {
return latest , nil
} else {
return earliest , nil
}
}
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func PriceHandler ( r * http . Request , tx * Tx ) ResponseWriterWriter {
user , err := GetUserFromSession ( tx , r )
if err != nil {
return NewError ( 1 /*Not Signed In*/ )
}
if r . Method == "POST" {
price_json := r . PostFormValue ( "price" )
if price_json == "" {
return NewError ( 3 /*Invalid Request*/ )
}
var price Price
err := price . Read ( price_json )
if err != nil {
return NewError ( 3 /*Invalid Request*/ )
}
price . PriceId = - 1
_ , err = GetSecurity ( tx , price . SecurityId , user . UserId )
if err != nil {
return NewError ( 3 /*Invalid Request*/ )
}
_ , err = GetSecurity ( tx , price . CurrencyId , user . UserId )
if err != nil {
return NewError ( 3 /*Invalid Request*/ )
}
err = tx . Insert ( & price )
if err != nil {
log . Print ( err )
return NewError ( 999 /*Internal Error*/ )
}
return ResponseWrapper { 201 , & price }
} else if r . Method == "GET" {
var priceid int64
n , err := GetURLPieces ( r . URL . Path , "/price/%d" , & priceid )
if err != nil || n != 1 {
//Return all prices
var pl PriceList
prices , err := GetPrices ( tx , user . UserId )
if err != nil {
log . Print ( err )
return NewError ( 999 /*Internal Error*/ )
}
pl . Prices = prices
return & pl
} else {
price , err := GetPrice ( tx , priceid , user . UserId )
if err != nil {
return NewError ( 3 /*Invalid Request*/ )
}
return price
}
} else {
priceid , err := GetURLID ( r . URL . Path )
if err != nil {
return NewError ( 3 /*Invalid Request*/ )
}
if r . Method == "PUT" {
price_json := r . PostFormValue ( "price" )
if price_json == "" {
return NewError ( 3 /*Invalid Request*/ )
}
var price Price
err := price . Read ( price_json )
if err != nil || price . PriceId != priceid {
return NewError ( 3 /*Invalid Request*/ )
}
_ , err = GetSecurity ( tx , price . SecurityId , user . UserId )
if err != nil {
return NewError ( 3 /*Invalid Request*/ )
}
_ , err = GetSecurity ( tx , price . CurrencyId , user . UserId )
if err != nil {
return NewError ( 3 /*Invalid Request*/ )
}
count , err := tx . Update ( & price )
if err != nil || count != 1 {
log . Print ( err )
return NewError ( 999 /*Internal Error*/ )
}
return & price
} else if r . Method == "DELETE" {
price , err := GetPrice ( tx , priceid , user . UserId )
if err != nil {
return NewError ( 3 /*Invalid Request*/ )
}
count , err := tx . Delete ( price )
if err != nil || count != 1 {
log . Print ( err )
return NewError ( 999 /*Internal Error*/ )
}
return SuccessWriter { }
}
}
return NewError ( 3 /*Invalid Request*/ )
}