Class: MIDB::API::Model

Inherits:
Object
  • Object
show all
Defined in:
lib/midb/server_model.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(jsf, db, engine) ⇒ Model

Constructor

Parameters:

  • jsf (String) —

    JSON file with the schema

  • db (String) —

    Database to operate on.

  • engine (Object) —

    Reference to the API engine.



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# File 'lib/midb/server_model.rb', line 20

def initialize(jsf, db, engine)
  @jsf = jsf
  @db = db
  @engine = engine
end

Instance Attribute Details

#db ⇒ Object

Returns the value of attribute db.



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# File 'lib/midb/server_model.rb', line 13

def db
  @db
end

#engine ⇒ Object

Returns the value of attribute engine.



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# File 'lib/midb/server_model.rb', line 13

def engine
  @engine
end

#jsf ⇒ Object

Returns the value of attribute jsf.



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# File 'lib/midb/server_model.rb', line 13

def jsf
  @jsf
end

Instance Method Details

#delete(id) ⇒ Object

Delete a resource

Parameters:

  • id (Fixnum) —

    ID to delete



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# File 'lib/midb/server_model.rb', line 189

def delete(id)
  # Check if the ID exists
  db = MIDB::API::Dbengine.new(@engine.config, @db)
  dbc = db.connect()
  dbq = db.query(dbc, "SELECT * FROM #{self.get_structure.values[0].split('/')[0]} WHERE id=#{id};")
  if not db.length(dbq) > 0
    resp = MIDB::Interface::Server.json_error(404, "ID not found").to_json
    @engine.http_status = 404
    bad_request = true
  else
    # ID Found, so let's delete it. (including linked resources!)
    jss = self.get_structure() # Referencing

    where_clause = {}
    tables = []
    main_table = jss.values[0].split('/')[0]
    where_clause[main_table] = "id=#{id}"

    jss.each do |k, v|
      table = v.split("/")[0]
      tables.push table unless tables.include? table
      # Check if it's a linked resource, generate WHERE clause accordingly
      if v.split("/").length > 2
        match = v.split("/")[2]
        matching_field = match.split("->")[0]
        row_field = match.split("->")[1]
        # We have to run the subquery now because it'll be deleted later!
        subq = "SELECT #{row_field} FROM #{main_table} WHERE #{where_clause[main_table]};"
        res = db.query(dbc, subq)
        subqres = db.extract(res, row_field)
        where_clause[table] ||= "#{matching_field}=#{subqres}"
      else
        # Normal WHERE clause
        where_clause[table] ||= "id=#{id}"
      end
    end

    # Generate and run queries
    results = []
    tables.each do |tb|
      query = "DELETE FROM #{tb} WHERE #{where_clause[tb]};"
      results.push db.query(dbc, query)
    end
    @engine.http_status = "200 OK"
    resp = {status: "200 OK"}
  end
  return resp
end

#get_all_entries ⇒ Object

Get all the entries from the database



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# File 'lib/midb/server_model.rb', line 276

def get_all_entries()
  jso = Hash.new()
     
  # Connect to database
  dbe = MIDB::API::Dbengine.new(@engine.config, @db)
  dblink = dbe.connect()
  rows = dbe.query(dblink, "SELECT * FROM #{self.get_structure.values[0].split('/')[0]};")

  # Iterate over all rows of this table
  rows.each do |row|
    # Replace the "id" in the given JSON with the actual ID and expand it with the fields
    jso[row["id"]] = self.get_structure

    self.get_structure.each do |name, dbi|
      table = dbi.split("/")[0]
      field = dbi.split("/")[1]
      # Must-match relations ("table2/field/table2-field->row-field")
      if dbi.split("/").length > 2
        match = dbi.split("/")[2]
        matching_field = match.split("->")[0]
        row_field = match.split("->")[1]
        query = dbe.query(dblink, "SELECT #{field} FROM #{table} WHERE #{matching_field}=#{row[row_field]};")
      else
        query = dbe.query(dblink, "SELECT #{field} from #{table} WHERE id=#{row['id']};")
      end
      jso[row["id"]][name] = dbe.length(query) > 0 ? dbe.extract(query,field) : "unknown"
    end
  end
  MIDB::API::Hooks.after_get_all_entries()
  return jso
end

#get_entries(id) ⇒ Object

Get an entry with a given id.

Parameters:

  • id (Fixnum) —

    ID of the entry



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# File 'lib/midb/server_model.rb', line 241

def get_entries(id)
  jso = Hash.new()

  dbe = MIDB::API::Dbengine.new(@engine.config, @db)
  dblink = dbe.connect()
  rows = dbe.query(dblink, "SELECT * FROM #{self.get_structure.values[0].split('/')[0]} WHERE id=#{id};")
  if dbe.length(rows) > 0
    rows.each do |row|
      jso[row["id"]] = self.get_structure

      self.get_structure.each do |name, dbi|
        table = dbi.split("/")[0]
        field = dbi.split("/")[1]
        # Must-match relations ("table2/field/table2-field->row-field")
        if dbi.split("/").length > 2
          match = dbi.split("/")[2]
          matching_field = match.split("->")[0]
          row_field = match.split("->")[1]
          query = dbe.query(dblink, "SELECT #{field} FROM #{table} WHERE #{matching_field}=#{row[row_field]};")
        else
          query = dbe.query(dblink, "SELECT #{field} from #{table} WHERE id=#{row['id']};")
        end
        jso[row["id"]][name] = dbe.length(query) > 0 ? dbe.extract(query,field) : "unknown"
      end
    end
    @engine.http_status = "200 OK"
  else
    @engine.http_status = "404 Not Found"
    jso = MIDB::Interface::Server.json_error(404, "Not Found")
  end
  return jso

end

#get_structure ⇒ Object

Safely get the structure



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# File 'lib/midb/server_model.rb', line 27

def get_structure()
  JSON.parse(IO.read("./json/#{@jsf}.json"))["id"]
end

#post(data) ⇒ Object

Act on POST requests - create a new resource

Parameters:

  • data (String) —

    The HTTP query string containing what to POST.



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# File 'lib/midb/server_model.rb', line 41

def post(data)
  jss = self.get_structure() # For referencing purposes

  input = self.query_to_hash(data)
  bad_request = false
  resp = nil
  jss.each do |key, value|
    # Check if we have it on the query too
    unless input.has_key? key
      resp = MIDB::Interface::Server.json_error(400, "Bad Request - Not enough data for a new resource")
      @engine.http_status = 400
      bad_request = true
    end
  end
  input.each do |key, value|
    # Check if we have it on the structure too
    unless jss.has_key? key
      resp = MIDB::Interface::Server.json_error(400, "Bad Request - Wrong argument #{key}")
      @engine.http_status = 400
      bad_request = true
    end
  end
  

  # Insert the values if we have a good request
  unless bad_request
    fields = Hash.new
    inserts = Hash.new
    main_table = self.get_structure.values[0].split('/')[0]
    input.each do |key, value|
      struct = jss[key]
      table = struct.split("/")[0]
      inserts[table] ||= []
      fields[table] ||= []
      inserts[table].push "\"" + value + "\""
      fields[table].push struct.split("/")[1]
      if struct.split("/").length > 2
        match = struct.split("/")[2]
        matching_field = match.split("->")[0]
        row_field = match.split("->")[1]
        fields[table].push matching_field
        if @engine.config["dbengine"] == :mysql
          inserts[table].push "(SELECT #{row_field} FROM #{main_table} WHERE id=(SELECT LAST_INSERT_ID()))"
        else
          inserts[table].push "(SELECT #{row_field} FROM #{main_table} WHERE id=(last_insert_rowid()))"
        end
      end
    end
    queries = []      
    inserts.each do |table, values|
      queries.push "INSERT INTO #{table}(#{fields[table].join(',')}) VALUES (#{inserts[table].join(',')});"
    end
    # Connect to the database
    dbe = MIDB::API::Dbengine.new(@engine.config, @db)
    dblink = dbe.connect()
    results = []
    rid = nil
    # Find the ID to return in the response (only for the first query)
    queries.each do |q|
      results.push dbe.query(dblink, q)
      if @engine.config["dbengine"] == :mysql
        rid ||= dbe.extract(dbe.query(dblink, "SELECT id FROM #{main_table} WHERE id=(SELECT LAST_INSERT_ID());"), "id")
      else
        rid ||= dbe.extract(dbe.query(dblink, "SELECT id FROM #{main_table} WHERE id=(last_insert_rowid());"), "id")
      end
    end
    @engine.http_status = "201 Created"
    resp = {status: "201 created", id: rid}
  end
  return resp
end

#put(id, data) ⇒ Object

Update an already existing resource

Parameters:

  • id (Fixnum) —

    ID to alter

  • data (String) —

    HTTP query string



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# File 'lib/midb/server_model.rb', line 117

def put(id, data)
  jss = self.get_structure() # For referencing purposes

  input = self.query_to_hash(data)
  bad_request = false
  resp = nil
  input.each do |key, value|
    # Check if we have it on the structure too
    unless jss.has_key? key
      resp = MIDB::Interface::Server.json_error(400, "Bad Request - Wrong argument #{key}")
      @engine.http_status = 400
      bad_request = true
    end
  end

  # Check if the ID exists
  db = MIDB::API::Dbengine.new(@engine.config, @db)
  dbc = db.connect()
  dbq = db.query(dbc, "SELECT * FROM #{self.get_structure.values[0].split('/')[0]} WHERE id=#{id};")
  unless db.length(dbq) > 0
    resp = MIDB::Interface::Server.json_error(404, "ID not found")
    @engine.http_status = 404
    bad_request = true
  end
  
  # Update the values if we have a good request
  unless bad_request
    fields = Hash.new
    inserts = Hash.new
    where_clause = Hash.new
    main_table = self.get_structure.values[0].split('/')[0]
    where_clause[main_table] = "id=#{id}"
    input.each do |key, value|
      struct = jss[key]
      table = struct.split("/")[0]
      inserts[table] ||= []
      fields[table] ||= []
      inserts[table].push "\"" + value + "\""
      fields[table].push struct.split("/")[1]
      if struct.split("/").length > 2
        match = struct.split("/")[2]
        matching_field = match.split("->")[0]
        row_field = match.split("->")[1]
        where_clause[table] = "#{matching_field}=(SELECT #{row_field} FROM #{main_table} WHERE #{where_clause[main_table]});"
      end
    end
    queries = []
    updates = Hash.new
    # Turn it into a hash
    inserts.each do |table, values|
      updates[table] ||= Hash.new
      updates[table] = Hash[fields[table].zip(inserts[table])]
      query = "UPDATE #{table} SET "
      updates[table].each do |f, v|
        query = query + "#{f}=#{v} "
      end
      queries.push query + "WHERE #{where_clause[table]};"
    end
    # Run the queries
    results = []
    queries.each do |q|
      results.push db.query(dbc, q)
    end
    @engine.http_status = "200 OK"
    resp = {status: "200 OK"}
  end
  return resp
end

#query_to_hash(query) ⇒ Object

Convert a HTTP query string to a JSONable hash

Parameters:

  • query (String) —

    HTTP query string



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# File 'lib/midb/server_model.rb', line 34

def query_to_hash(query)
  Hash[CGI.parse(query).map {|key,values| [key, values[0]||true]}]
end