Cal. Pen. Code § 1550.1
No person arrested upon such warrant shall be delivered over to the agent of the executive authority demanding him unless he is first taken forthwith before a magistrate, who shall inform him of the demand made for his surrender, and of the crime with which he is charged, and that he has the right to demand and procure counsel. If the accused or his counsel desires to test the legality of the arrest, the magistrate shall remand the accused to custody, and fix a reasonable time to be allowed him within which to apply for a writ of habeas corpus. If the writ is denied, and probable cause appears for an application for a writ of habeas corpus to another court, or justice or judge thereof, the order denying the writ shall remand the accused to custody, and fix a reasonable time within which the accused may again apply for a writ of habeas corpus. When an application is made for a writ of habeas corpus as contemplated by this section, a copy of the application shall be served as provided in Section 1475, upon the district attorney of the county in which the accused is in custody, and upon the agent of the demanding state. A warrant issued in accordance with the provisions of Section 1549.2 shall be presumed to be valid, and unless a court finds that the person in custody is not the same person named in the warrant, or that the person is not a fugitive from justice, or otherwise subject to extradition under Section 1549.1, or that there is no criminal charge or criminal proceeding pending against the person in the demanding state, or that the documents are not on their face in order, the person named in the warrant shall be held in custody at all times, and shall not be eligible for release on bail.
Ca. Pen. Code § 1550.1