How to Unmarshall key-less JSON array in Golang correctly?

I have JSON data which looks like this:

[
  {
    "globalTradeID": 64201000,
    "tradeID": 549285,
    "date": "2016-11-11 23:51:58",
    "type": "buy",
    "rate": "10.33999779",
    "amount": "0.02176472",
    "total": "0.22504715"
  },
  {
    "globalTradeID": 64200631,
    "tradeID": 549284,
    "date": "2016-11-11 23:48:39",
    "type": "buy",
    "rate": "10.33999822",
    "amount": "0.18211700",
    "total": "1.88308945"
  }...
]

I've tried to unmarshall this JSON by defining a type:

type TradeHistoryResponse 	[]TradeHistoryInfo

type TradeHistoryInfo struct {
	GlobalTradeID 	int64 	`json:"globalTradeID"`
	TradeID 		int64 	`json:"tradeID"`
	Date 			string 	`json:"date"`
	Type 			string 	`json:"type"`
	Rate 			float64 `json:"rate,string"`
	Amount 			float64 `json:"amount,string"`
	Total 			float64 `json:"total,string"`
}

And then pulling the JSON data as so:

	//Read response
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("[Poloniex] (doRequest) Failed to parse response for query to %s! (%s)", reqURL, err.Error())
	} 

	//Convert JSON to struct
    
	var THR TradeHistoryResponse
    err = json.Unmarshal(body, &THR)
	if err != nil {
		return nil, fmt.Errorf("[Poloniex] (doRequest) Failed to convert response into JSON for query to %s! (%s)", reqURL, err.Error())
	}

I get the following error:

(json: cannot unmarshal object into Go value of type poloniex.TradeHistoryResponse)

My best guess why the Unmarshall doesn't work is because the array is key-less?

Would love to have some clarification on the matter on how I might best get this working.

I didn't think unmarhsalling an array in a JSON like you intended actually works but to the props of encoding/json it does. Example code:
package main

import (
	"encoding/json"
	"fmt"
	"log"
)

var mjs string = "[" +
	"{" +
	`"globalTradeID": 64201000,
                          "tradeID": 549285,
                          "date": "2016-11-11 23:51:58",
                          "type": "buy",
                          "rate": "10.33999779",
                          "amount": "0.02176472",
                          "total": "0.22504715"
                        },
                        {
                          "globalTradeID": 64200631,
                          "tradeID": 549284,
                          "date": "2016-11-11 23:48:39",
                          "type": "buy",
                          "rate": "10.33999822",
                          "amount": "0.18211700",
                          "total": "1.88308945"
                        }
                        ]`

type TradeHistoryResponse []TradeHistoryInfo

type TradeHistoryInfo struct {
	GlobalTradeID int64   `json:"globalTradeID"`
	TradeID       int64   `json:"tradeID"`
	Date          string  `json:"date"`
	Type          string  `json:"type"`
	Rate          float64 `json:"rate,string"`
	Amount        float64 `json:"amount,string"`
	Total         float64 `json:"total,string"`
}

func main() {

	//Convert JSON to struct

	var THR TradeHistoryResponse
	err := json.Unmarshal([]byte(mjs), &THR)
	if err != nil {
    log.Fatal(err)
	}
  for _, v := range THR {
    fmt.Printf("%+v", v)
    fmt.Printf("\n")
  }
}

This prints out all the values as expected. So it doesn't have a problem converting the json values to float/int either (which would have been my second guess).

Are you sure you aren't modifying the Body in any way ? And that the example you give cover all edge cases ?

Could you add:

fmt.Println(string(body)) 

to the second error block and log the error it give here.

Also what version of go are you using ? I wouldn't exclude the possibility of encoding/json to have changed between versions. In the end, if this is indeed the case the easy fix would be taking your response as a string, removing all whitespaces and splitting at "}'{" as in:

fmtBody := strings.Replace(string(body), "\n", "", -1)
fmtBody = strings.Replace(string(fmtBody), "\w", "", -1)
fmtBody = strings.Replace(string(fmtBody), "[", "", -1)
fmtBody = strings.Replace(string(fmtBody), "]", "", -1)
var goArrOfYourJsonsObj []String = strings.Split(fmtBody, "},{")
for k, _ := range goArrOfYourJsonsObj {
  goArrOfYourJsonsObj[k] += "}"
}

And now you have your JSON objects neatly separated into a go array of types String which, can be used in Unmarshall as []byte(val).

TradeHistoryResponse is a type no a variable, you have to create a var of type TradeHistoryResponse, like this:

var th TradeHistoryResponse

//Convert JSON to struct
err = json.Unmarshal(body, &th)
// ...

fmt.Printf("%+v\n", th)