Document System Tutorial Part 12 - Custom Count function

In this part, we will discuss about creating a custom Count function that checks the query and the UserID.

Go to document.go inside the models folder and create a function named Count that holds a, query, and args as an array of interface. args… means you can assign multiple values inside the function parameters.

// Count !
func (d Document) Count(a interface{}, query interface{}, args ...interface{}) int {
    // Some codes
}

Inside the function, convert a query parameter into a string. We will use that for some validation process later.

// Converts the query into a string
Q := fmt.Sprint(query)

Let’s check whether the string contains a query and a UserID.

if strings.Contains(Q, "user_id = ?") {
    // Some codes
}

Inside the if statement, we have to split the query part by part for multiple queries.

// Split the query part by part
qParts := strings.Split(Q, " AND ")

Initialize two variables for the query and an argument.

// Initialize tempArgs as an interface and tempQuery as a string
tempArgs := []interface{}{}
tempQuery := []string{}

Create a for loop statement that checks whether the specific query part is not equal to the UserID value. If it does, append the specific query part and arguments in a single variable.

// Loop the query every part
for i := range qParts {
    // Checks whether the specific query part is not equal to the
    // UserID value
    if qParts[i] != "user_id = ?" {
        // Append the arguments into the tempArgs variable
        tempArgs = append(tempArgs, args[i])

        // Append the specific query part into the tempQuery variable
        tempQuery = append(tempQuery, qParts[i])
    }
}

Now concatenate the tempQuery into the query variable to create a single string.

// Concatenate the query to create a single string
query = strings.Join(tempQuery, " AND ")

Assign tempArgs object into the args variable.

// Assign tempArgs object into the args variable
args = tempArgs

Outside the strings.Contains(Q, “user_id = ?”) if statement, return the a, query, and args… inside the Count function parameters.

// Return the a, query, and args... inside the Count function parameters
return uadmin.Count(a, query, args...)

Click here to view our progress so far.

In the next part, we will talk about creating a custom AdminPage function that checks the query and the UserID.

• Document System Tutorial Part 12 - Custom Count function (Current Progress)