Hallo!

OK, ich weiss bereits, dass man mit

markieren

Code:

...
IdHTTP1.Head('http://www.meineseite.de/datei.htm');
Edit1.Text := IntToStr(IdHTTP1.Response.ContentLength);
...

die Größe der zu ladenden Datei, in diesem Fall einer HTML-Datei, ermitteln kann. Wird dabei den ganzen Quelltext der Datei zurückgegeben, genauso wie beim IdHTTP.Get, oder wirklich nur die Header-Informationen?

du kannst einen custom header im indy angeben in den du nur 1 byte anforderst.

schau hier:
http://www.w3.org/Protocols/rfc2616/rfc2616.txt

Range -> Section 14.35

steht nix anderes als muss der server koennen und sagst
"range 1-2"

markieren

Code:

14.35 Range

14.35.1 Byte Ranges

   Since all HTTP entities are represented in HTTP messages as sequences
   of bytes, the concept of a byte range is meaningful for any HTTP
   entity. (However, not all clients and servers need to support byte-
   range operations.)

   Byte range specifications in HTTP apply to the sequence of bytes in
   the entity-body (not necessarily the same as the message-body).

   A byte range operation MAY specify a single range of bytes, or a set
   of ranges within a single entity.

       ranges-specifier = byte-ranges-specifier
       byte-ranges-specifier = bytes-unit "=" byte-range-set
       byte-range-set = 1#( byte-range-spec | suffix-byte-range-spec )
       byte-range-spec = first-byte-pos "-" [last-byte-pos]
       first-byte-pos = 1*DIGIT
       last-byte-pos  = 1*DIGIT

   The first-byte-pos value in a byte-range-spec gives the byte-offset
   of the first byte in a range. The last-byte-pos value gives the
   byte-offset of the last byte in the range; that is, the byte
   positions specified are inclusive. Byte offsets start at zero.

   If the last-byte-pos value is present, it MUST be greater than or
   equal to the first-byte-pos in that byte-range-spec, or the byte-
   range-spec is syntactically invalid. The recipient of a byte-range-
   set that includes one or more syntactically invalid byte-range-spec
   values MUST ignore the header field that includes that byte-range-
   set.

   If the last-byte-pos value is absent, or if the value is greater than
   or equal to the current length of the entity-body, last-byte-pos is
   taken to be equal to one less than the current length of the entity-
   body in bytes.

   By its choice of last-byte-pos, a client can limit the number of
   bytes retrieved without knowing the size of the entity.




Fielding, et al.           Standards Track                  [Page 138]

RFC 2616                        HTTP/1.1                       June 1999


       suffix-byte-range-spec = "-" suffix-length
       suffix-length = 1*DIGIT

   A suffix-byte-range-spec is used to specify the suffix of the
   entity-body, of a length given by the suffix-length value. (That is,
   this form specifies the last N bytes of an entity-body.) If the
   entity is shorter than the specified suffix-length, the entire
   entity-body is used.

   If a syntactically valid byte-range-set includes at least one byte-
   range-spec whose first-byte-pos is less than the current length of
   the entity-body, or at least one suffix-byte-range-spec with a non-
   zero suffix-length, then the byte-range-set is satisfiable.
   Otherwise, the byte-range-set is unsatisfiable. If the byte-range-set
   is unsatisfiable, the server SHOULD return a response with a status
   of 416 (Requested range not satisfiable). Otherwise, the server
   SHOULD return a response with a status of 206 (Partial Content)
   containing the satisfiable ranges of the entity-body.

   Examples of byte-ranges-specifier values (assuming an entity-body of
   length 10000):

      - The first 500 bytes (byte offsets 0-499, inclusive): bytes=0-
        499

      - The second 500 bytes (byte offsets 500-999, inclusive):
        bytes=500-999

      - The final 500 bytes (byte offsets 9500-9999, inclusive):
        bytes=-500

      - Or bytes=9500-

      - The first and last bytes only (bytes 0 and 9999): bytes=0-0,-1

      - Several legal but not canonical specifications of the second 500
        bytes (byte offsets 500-999, inclusive):
         bytes=500-600,601-999
         bytes=500-700,601-999

14.35.2 Range Retrieval Requests

   HTTP retrieval requests using conditional or unconditional GET
   methods MAY request one or more sub-ranges of the entity, instead of
   the entire entity, using the Range request header, which applies to
   the entity returned as the result of the request:

      Range = "Range" ":" ranges-specifier



Fielding, et al.           Standards Track                  [Page 139]

RFC 2616                        HTTP/1.1                       June 1999


   A server MAY ignore the Range header. However, HTTP/1.1 origin
   servers and intermediate caches ought to support byte ranges when
   possible, since Range supports efficient recovery from partially
   failed transfers, and supports efficient partial retrieval of large
   entities.

   If the server supports the Range header and the specified range or
   ranges are appropriate for the entity:

      - The presence of a Range header in an unconditional GET modifies
        what is returned if the GET is otherwise successful. In other
        words, the response carries a status code of 206 (Partial
        Content) instead of 200 (OK).

      - The presence of a Range header in a conditional GET (a request
        using one or both of If-Modified-Since and If-None-Match, or
        one or both of If-Unmodified-Since and If-Match) modifies what
        is returned if the GET is otherwise successful and the
        condition is true. It does not affect the 304 (Not Modified)
        response returned if the conditional is false.

   In some cases, it might be more appropriate to use the If-Range
   header (see section 14.27) in addition to the Range header.

   If a proxy that supports ranges receives a Range request, forwards
   the request to an inbound server, and receives an entire entity in
   reply, it SHOULD only return the requested range to its client. It
   SHOULD store the entire received response in its cache if that is
   consistent with its cache allocation policies.

Nur der Header denke ich, sonst wäre es ja sinnlos.