72 lines
1.8 KiB
Go
72 lines
1.8 KiB
Go
package server
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import (
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"io"
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"net/http"
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"reflect"
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"l12.xyz/dal/adapter"
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"l12.xyz/dal/proto"
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)
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/**
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* QueryHandler is a http.Handler that reads a proto.Request from the request body,
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* parses it into a query, executes the query on the provided db and writes the
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* result to the response body.
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* - The request body is expected to be in msgpack format (proto.Request).
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* - The response body is written in msgpack format.
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* - The respose is a stream of rows (proto.Row), where the first row is the column names.
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* - The columns are sorted alphabetically, so it is client's responsibility to match them and sort as needed.
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**/
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func QueryHandler(db adapter.DBAdapter) http.Handler {
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dialect := adapter.GetDialect(db.Type)
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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bodyReader, err := r.GetBody()
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if err != nil {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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body, err := io.ReadAll(bodyReader)
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if err != nil {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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req := proto.Request{}
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req.UnmarshalMsg(body)
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query, err := req.Parse(dialect)
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if err != nil {
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http.Error(w, err.Error(), http.StatusBadRequest)
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return
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}
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rows, err := db.Query(query)
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if err != nil {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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defer rows.Close()
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w.Header().Set("Content-Type", "application/x-msgpack")
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columns, _ := rows.Columns()
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types, _ := rows.ColumnTypes()
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cols, _ := proto.MarshalRow(columns)
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w.Write(cols)
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for rows.Next() {
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data := make([]interface{}, len(columns))
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for i := range data {
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typ := reflect.New(types[i].ScanType()).Interface()
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data[i] = &typ
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}
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rows.Scan(data...)
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cols, _ := proto.MarshalRow(data)
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w.Write(cols)
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}
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})
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}
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