92 lines
2.1 KiB
Go
92 lines
2.1 KiB
Go
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package common
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// WhereClause is a struct representing a where clause.
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// This is made to easily create WHERE clauses from parameters passed from a request.
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type WhereClause struct {
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Clause string
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Params []interface{}
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useOr bool
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}
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// Where adds a new WHERE clause to the WhereClause.
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func (w *WhereClause) Where(clause, passedParam string, allowedValues ...string) *WhereClause {
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if passedParam == "" {
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return w
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}
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if len(allowedValues) != 0 && !contains(allowedValues, passedParam) {
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return w
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}
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w.addWhere()
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w.Clause += clause
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w.Params = append(w.Params, passedParam)
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return w
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}
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func (w *WhereClause) addWhere() {
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// if string is empty add "WHERE", else add AND
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if w.Clause == "" {
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w.Clause += "WHERE "
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} else {
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if w.useOr {
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w.Clause += " OR "
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return
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}
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w.Clause += " AND "
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}
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}
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// Or enables using OR instead of AND
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func (w *WhereClause) Or() *WhereClause {
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w.useOr = true
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return w
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}
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// And enables using AND instead of OR
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func (w *WhereClause) And() *WhereClause {
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w.useOr = false
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return w
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}
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// In generates an IN clause.
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// initial is the initial part, e.g. "users.id".
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// Fields are the possible values.
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// Sample output: users.id IN ('1', '2', '3')
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func (w *WhereClause) In(initial string, fields ...[]byte) *WhereClause {
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if len(fields) == 0 {
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return w
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}
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w.addWhere()
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w.Clause += initial + " IN (" + generateQuestionMarks(len(fields)) + ")"
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fieldsInterfaced := make([]interface{}, len(fields))
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for k, f := range fields {
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fieldsInterfaced[k] = string(f)
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}
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w.Params = append(w.Params, fieldsInterfaced...)
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return w
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}
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func generateQuestionMarks(x int) (qm string) {
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for i := 0; i < x-1; i++ {
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qm += "?, "
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}
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if x > 0 {
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qm += "?"
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}
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return qm
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}
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// ClauseSafe returns the clause, always containing something. If w.Clause is
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// empty, it returns "WHERE 1".
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func (w *WhereClause) ClauseSafe() string {
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if w.Clause == "" {
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return "WHERE 1"
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}
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return w.Clause
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}
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// Where is the same as WhereClause.Where, but creates a new WhereClause.
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func Where(clause, passedParam string, allowedValues ...string) *WhereClause {
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w := new(WhereClause)
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return w.Where(clause, passedParam, allowedValues...)
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}
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