Mercurial > hg > cc > cirrus_work
annotate bin/warc.py @ 48:d0d2fd9830d6
starting on conversion to direct-querying of buffer
| author | Henry S. Thompson <ht@inf.ed.ac.uk> |
|---|---|
| date | Thu, 06 Jul 2023 13:27:33 +0100 |
| parents | 44d3a4f4ea51 |
| children | 699ef141af10 |
| rev | line source |
|---|---|
| 39 | 1 #!/usr/bin/env python3 |
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2 '''Stream a warc format file, unzipping if necessary, invoking a |
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3 callback on each record. Callback can be limited by WARC-Type, record |
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4 part''' |
| 39 | 5 |
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6 import sys,io |
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7 from isal import igzip |
| 39 | 8 |
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9 def warc(filename,callback,types=['response'],whole=False,parts=7,debug=False): |
| 39 | 10 types=[(t if isinstance(t,bytes) else bytes(t,'utf8')) for t in types] |
| 11 nb=0 | |
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12 if filename.endswith(".gz"): |
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13 stream=igzip.IGzipFile(filename=filename) |
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14 else: |
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15 stream=open(filename,'rb',0) |
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16 bufSize=2*1024*1024 |
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17 hdrMax=16*1024 |
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18 buf=bytearray(bufSize) |
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19 hdrBuf=memoryview(buf)[:hdrMax] |
| 39 | 20 while not stream.closed: |
| 21 bp=0 | |
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22 bl=stream.readinto(hdrBuf) |
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23 if bl==0: |
| 43 | 24 break |
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25 while buf.startswith(b'\r\n',bp): |
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26 bp+=2 |
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27 if not buf.startswith(b'WARC/1.0\r\n',bp): |
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28 raise ValueError("Not a WARC file? At %s: %s[%s]"%(bp, |
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29 buf[bp:min(bl,bp+20)].decode('latin-1'), bl-bp)) |
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30 bob=bp # in case 1 or whole |
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31 bp+=10 |
| 39 | 32 wtype=None |
| 33 length=None | |
| 34 state=1 | |
| 35 tr=None # Was this record truncated? | |
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36 while not buf.startswith(b'\r\n',bp): |
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37 print('yes',) |
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38 eol=buf.index(b'\r\n',bp)+2 |
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39 if buf.startswith(b"Content-Length: ",bp): |
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40 length=wl=int(buf[bp+16:eol-2]) |
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41 elif buf.startswith(b"WARC-Truncated: ",bp): |
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42 tr=l[bp+16:eol-2] |
| 39 | 43 tr="EMPTY" if tr=="" else tr |
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44 elif buf.startswith(b'WARC-Type: ',bp): |
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45 wtype = bytes(buf[bp+11:eol-2]) |
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46 bp=eol |
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47 start_2=eol |
| 39 | 48 if (wtype in types): |
| 49 if whole: | |
| 50 buf[bp:(bp:=bp+ln)]=l | |
| 51 elif (parts & 1): | |
| 52 callback(wtype,buf[:start_2],1) | |
| 53 if parts==1: | |
| 54 start_2=0 | |
| 55 else: | |
| 56 start_2=bp | |
| 57 else: | |
| 58 start_2=0 | |
| 59 bv=memoryview(buf)[start_2:start_2+length] | |
| 60 ii=0 | |
| 61 while True and not stream.closed: | |
| 62 if (i:=stream.readinto(bv))==0: | |
| 63 break | |
| 64 ii+=i | |
| 65 if ii>=length: | |
| 66 break | |
| 67 bv=memoryview(buf)[start_2+ii:start_2+length] | |
| 68 if ii!=length: | |
| 69 raise ValueError("Chunk read losing, from %s got %s expected %s"%(nb,ii,length)) | |
| 70 nb+=length | |
| 71 if wtype in types: | |
| 72 if whole: | |
| 73 callback(wtype,buf[0:start_2+length],7) | |
| 74 continue | |
| 75 # Only output parts (1 = WARC header, 2 = HTTP header, 4 = body) that are wanted | |
| 76 bl=None # for HTTP Content-Length for the length of the body? | |
| 77 L_start=start_2 | |
| 78 state=2 | |
| 79 bv=memoryview(buf)[start_2:start_2+length] | |
| 80 with io.BytesIO(bv) as rec_text: | |
| 81 for L in rec_text: | |
| 82 if state==2: | |
| 83 # HTTP header | |
| 84 wl -= len(L) | |
| 85 if not (L==b"" or L.startswith(b"\r")): | |
| 86 # Non-empty, it's (a continuation of) a header | |
| 87 if bl is None and L.startswith(b"Content-Length: "): | |
| 88 bl=int(L[16:].rstrip()) | |
| 89 else: | |
| 90 # Blank line, HTTP header is finished | |
| 91 if parts & 2: | |
| 92 callback(wtype,buf[start_2:start_2+L_start],2) | |
| 93 state=4 | |
| 94 # The above is just for sanity, because we do _not_ | |
| 95 # continue with the outer loop, | |
| 96 # since we can now block-output the entire rest of the | |
| 97 # input buffer. | |
| 98 if bl is not None: | |
| 99 if bl!=wl: | |
| 100 print("length mismatch: %s %s %s here: %s given: %s trunc: %s"%\ | |
| 101 (length,offset,filename,wl,bl,tr),file=sys.stderr) | |
| 102 # HTTP body | |
| 103 balance=start_2+rec_text.tell() | |
| 104 #print(balance,bl,wl,ll,ll-balance,file=sys.stderr) | |
| 105 # Output whatever is left | |
| 106 if parts & 4: | |
| 107 callback(wtype,buf[balance:balance+wl],4) | |
| 108 state=1 | |
| 109 | |
| 110 L_start=rec_text.tell() |