Golang find a value from a map of nested json data from MongoDB

Question

I am trying to receive data from my MongoDB using MGO in a map of type []map[string]interface{}

My JSON looks like this -

{
   "_id":"string",
   "brandId":123,
   "category":{
      "television":[
         {
            "cat":"T1",
            "subCategory":[
               {
                  "subCat":"T1A TV",
                  "warrantyPeriod":6
               }
            ],
            "warrantyPeriod":12
         },
         {
            "cat":"T2",
            "subCategory":[
               {
                  "subCat":"T2A",
                  "warrantyPeriod":18
               },
               {
                  "subCat":"T2B",
                  "warrantyPeriod":9
               }
            ],
            "warrantyPeriod":15
         },
         {
            "cat":"T3",
            "subCategory":[
               {
                  "subCat":"T3A",
                  "warrantyPeriod":3
               },
               {
                  "subCat":"T3B",
                  "warrantyPeriod":5
               },
               {
                  "subCat":"T3C",
                  "warrantyPeriod":7
               },
               {
                  "subCat":"T3D",
                  "warrantyPeriod":11
               }
            ],
            "warrantyPeriod":4
         }
      ],
      "television_warrantyPeriod":24
   },
   "title":"BrandName"
}

I would ideally pass in the category name i.e. 'television' and cat and subCat values which could be optional.

For e.g. something like this -

{
"categorySlug": "television",
"brandId": "123",
"model": "T2"
}

In which case I would expect to find '15' which is the warrantyPeriod value for T2 if there are no T2A or T2B specified.

My query functions look like this -

var data map[string]string
err := json.NewDecoder(r.Body).Decode(&data)
log.Println(err)
var buffer bytes.Buffer
buffer.WriteString("category.")
buffer.WriteString(data["categorySlug"])
brandId, _ := strconv.Atoi(data["brandId"])
concernedbrandandcategory := database.GetMappedFields("Brands", bson.M{"brandId": brandId, buffer.String(): bson.M{"$exists": true}}, bson.M{buffer.String(): 1})
categorymap := concernedbrandandcategory[0]
log.Println(categorymap["category"]["television"], reflect.TypeOf(categorymap))

My GetMappedFields function looks like this -

func GetMappedFields(collectionName string, query interface{}, selector interface{}) (result []map[string]interface{}) {
    MgoSession.DB(Dbname).C(collectionName).Find(query).Select(selector).All(&result)
    return
}

I'm just not able to wrap my head around this nested structure which sometimes returns a map and sometimes an interface! Any help would be highly appreciated!

Abhishek Soni · Accepted Answer · 2016-09-08 06:10:45Z

1

you can do something like this

    majorCat := body["categorySlug"]
    category := body["category"]
    subCategory := body["subCategory"]
    brandId, err := strconv.Atoi(body["brandId"])
    if err != nil {
        log.Println(err)
    }
    result := database.GetMappedFields("Brands", bson.M{"brandId": brandId}, bson.M{"category": 1, "_id": 0})
    internalObj := result[0]["category"].(map[string]interface{})
    finalValue := internalObj["television_warrantyPeriod"]
    if category != "" {
        for _, v := range internalObj[majorCat].([]interface{}) {
            subObj := v.(map[string]interface{})
            if subObj["cat"] == category {
                finalValue = subObj["warrantyPeriod"]
                if subCategory != "" {
                    minorObj := subObj["subCategory"].([]interface{})
                    for _, iter := range minorObj {
                        kevVal := iter.(map[string]interface{})
                        if kevVal["subCat"] == subCategory {
                            finalValue = kevVal["warrantyPeriod"]
                        }
                    }
                }
            }
        }
    }

Hopefully this will do dynamically or you can create a struct so that it can directly be decoded into that cheers

answered Sep 8, 2016 at 6:10

Abhishek Soni

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1 Comment

Gaurav Ojha Over a year ago

Awesome! This is what I needed!

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